MVAPICH Environment Variables

Author:

MVAPICH Team

Date:

2025/03/07

CVAR Environment Variables

These are set as environment variables setting the CVAR or it’s alias to potential values. For example, setting the barrier intra-node algorithm:

MVP_BARRIER_INTRA_ALGORITHM="osu_pairwise"

---

MPIR_CVAR_BARRIER_INTRA_ALGORITHM

• Aliases: - MVP_BARRIER_INTRA_ALGORITHM

  • MPICH_BARRIER_INTRA_ALGORITHM

• Description: - Variable to select barrier algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - Force nonblocking algorithm

  • smp - - Force smp algorithm

  • k_dissemination - Force high radix dissemination algorithm

  • recexch - Force recursive exchange algorithm

  • osu_pairwise - Force OSU mcast based design

• Default: MPIR_CVAR_BARRIER_INTRA_ALGORITHM_auto

MPIR_CVAR_BARRIER_INTER_ALGORITHM

• Aliases: - MVP_BARRIER_INTER_ALGORITHM

  • MPICH_BARRIER_INTER_ALGORITHM

• Description: - Variable to select barrier algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • bcast - Force bcast algorithm

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_BARRIER_INTER_ALGORITHM_auto

MPIR_CVAR_BARRIER_DISSEM_KVAL

• Aliases: - MVP_BARRIER_DISSEM_KVAL

  • MPICH_BARRIER_DISSEM_KVAL

• Description: - k value for dissemination exchange based barrier algorithm

• Default: 2

MPIR_CVAR_BARRIER_RECEXCH_KVAL

• Aliases: - MVP_BARRIER_RECEXCH_KVAL

  • MPICH_BARRIER_RECEXCH_KVAL

• Description: - k value for recursive exchange based allreduce based

  • barrier

• Default: 2

MPIR_CVAR_BARRIER_RECEXCH_SINGLE_PHASE_RECV

• Aliases: - MVP_BARRIER_RECEXCH_SINGLE_PHASE_RECV

  • MPICH_BARRIER_RECEXCH_SINGLE_PHASE_RECV

• Description: - This CVAR controls whether the recv is posted for one

  • phase or two phases in recexch algos. By default, we post the recvs

  • for 2 phases.

• Default: 0

MPIR_CVAR_IBARRIER_RECEXCH_KVAL

• Aliases: - MVP_IBARRIER_RECEXCH_KVAL

  • MPICH_IBARRIER_RECEXCH_KVAL

• Description: - k value for recursive exchange based ibarrier

• Default: 2

MPIR_CVAR_IBARRIER_DISSEM_KVAL

• Aliases: - MVP_IBARRIER_DISSEM_KVAL

  • MPICH_IBARRIER_DISSEM_KVAL

• Description: - k value for dissemination exchange based ibarrier

• Default: 2

MPIR_CVAR_IBARRIER_INTRA_ALGORITHM

• Aliases: - MVP_IBARRIER_INTRA_ALGORITHM

  • MPICH_IBARRIER_INTRA_ALGORITHM

• Description: - Variable to select ibarrier algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_recursive_doubling - Force recursive doubling algorithm

  • tsp_recexch - Force generic transport based recursive exchange

  • algorithm

  • tsp_k_dissemination - Force generic transport based high-radix

  • dissemination algorithm

• Default: MPIR_CVAR_IBARRIER_INTRA_ALGORITHM_auto

MPIR_CVAR_IBARRIER_INTER_ALGORITHM

• Aliases: - MVP_IBARRIER_INTER_ALGORITHM

  • MPICH_IBARRIER_INTER_ALGORITHM

• Description: - Variable to select ibarrier algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_bcast - Force bcast algorithm

• Default: MPIR_CVAR_IBARRIER_INTER_ALGORITHM_auto

MPIR_CVAR_BCAST_MIN_PROCS

• Aliases: - MVP_BCAST_MIN_PROCS

  • MPICH_BCAST_MIN_PROCS

• Description: - Let’s define short messages as messages with size <

  • MPIR_CVAR_BCAST_SHORT_MSG_SIZE, and medium messages as messages

  • with size >= MPIR_CVAR_BCAST_SHORT_MSG_SIZE but <

  • MPIR_CVAR_BCAST_LONG_MSG_SIZE, and long messages as messages with

  • size >= MPIR_CVAR_BCAST_LONG_MSG_SIZE. The broadcast algorithms

  • selection procedure is as follows. For short messages or when the

  • number of processes is < MPIR_CVAR_BCAST_MIN_PROCS, we do broadcast

  • using the binomial tree algorithm. Otherwise, for medium messages

  • and with a power-of-two number of processes, we do broadcast based

  • on a scatter followed by a recursive doubling allgather algorithm.

  • Otherwise, for long messages or with non power-of-two number of

  • processes, we do broadcast based on a scatter followed by a ring

  • allgather algorithm. (See also: MPIR_CVAR_BCAST_SHORT_MSG_SIZE,

  • MPIR_CVAR_BCAST_LONG_MSG_SIZE)

• Default: 8

MPIR_CVAR_BCAST_SHORT_MSG_SIZE

• Aliases: - MVP_BCAST_SHORT_MSG_SIZE

  • MPICH_BCAST_SHORT_MSG_SIZE

• Description: - Let’s define short messages as messages with size <

  • MPIR_CVAR_BCAST_SHORT_MSG_SIZE, and medium messages as messages

  • with size >= MPIR_CVAR_BCAST_SHORT_MSG_SIZE but <

  • MPIR_CVAR_BCAST_LONG_MSG_SIZE, and long messages as messages with

  • size >= MPIR_CVAR_BCAST_LONG_MSG_SIZE. The broadcast algorithms

  • selection procedure is as follows. For short messages or when the

  • number of processes is < MPIR_CVAR_BCAST_MIN_PROCS, we do broadcast

  • using the binomial tree algorithm. Otherwise, for medium messages

  • and with a power-of-two number of processes, we do broadcast based

  • on a scatter followed by a recursive doubling allgather algorithm.

  • Otherwise, for long messages or with non power-of-two number of

  • processes, we do broadcast based on a scatter followed by a ring

  • allgather algorithm. (See also: MPIR_CVAR_BCAST_MIN_PROCS,

  • MPIR_CVAR_BCAST_LONG_MSG_SIZE)

• Default: 12288

MPIR_CVAR_BCAST_LONG_MSG_SIZE

• Aliases: - MVP_BCAST_LONG_MSG_SIZE

  • MPICH_BCAST_LONG_MSG_SIZE

• Description: - Let’s define short messages as messages with size <

  • MPIR_CVAR_BCAST_SHORT_MSG_SIZE, and medium messages as messages

  • with size >= MPIR_CVAR_BCAST_SHORT_MSG_SIZE but <

  • MPIR_CVAR_BCAST_LONG_MSG_SIZE, and long messages as messages with

  • size >= MPIR_CVAR_BCAST_LONG_MSG_SIZE. The broadcast algorithms

  • selection procedure is as follows. For short messages or when the

  • number of processes is < MPIR_CVAR_BCAST_MIN_PROCS, we do broadcast

  • using the binomial tree algorithm. Otherwise, for medium messages

  • and with a power-of-two number of processes, we do broadcast based

  • on a scatter followed by a recursive doubling allgather algorithm.

  • Otherwise, for long messages or with non power-of-two number of

  • processes, we do broadcast based on a scatter followed by a ring

  • allgather algorithm. (See also: MPIR_CVAR_BCAST_MIN_PROCS,

  • MPIR_CVAR_BCAST_SHORT_MSG_SIZE)

• Default: 524288

MPIR_CVAR_MAX_SMP_BCAST_MSG_SIZE

• Aliases: - MVP_MAX_SMP_BCAST_MSG_SIZE

  • MPICH_MAX_SMP_BCAST_MSG_SIZE

• Description: - Maximum message size for which SMP-aware broadcast is

  • used. A value of ‘0’ uses SMP-aware broadcast for all message

  • sizes.

• Default: 0

MPIR_CVAR_BCAST_INTRA_ALGORITHM

• Aliases: - MVP_BCAST_INTRA_ALGORITHM

  • MPICH_BCAST_INTRA_ALGORITHM

• Description: - Variable to select bcast algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • binomial - - - - - Force Binomial Tree

  • nb - - - - - Force nonblocking

  • algorithm

  • smp - - - - - Force smp algorithm

  • scatter_recursive_doubling_allgather - Force Scatter

  • Recursive-Doubling Allgather

  • scatter_ring_allgather - - - Force Scatter Ring

  • pipelined_tree - - - - Force tree-based

  • pipelined algorithm

  • tree - - - - - Force tree-based

  • algorithm

  • osu_knomial - - - - Force OSU knomial

  • algorithm

  • osu_pairwise - - - - Force OSU pairwise

  • algorithm

  • osu_pipelined - - - - Force OSU pipelined

  • algorithm

• Default: MPIR_CVAR_BCAST_INTRA_ALGORITHM_auto

MPIR_CVAR_BCAST_TREE_KVAL

• Aliases: - MVP_BCAST_TREE_KVAL

  • MPICH_BCAST_TREE_KVAL

• Description: - k value for tree (kary, knomial, etc.) based bcast

• Default: 2

MPIR_CVAR_BCAST_TREE_TYPE

• Aliases: - MVP_BCAST_TREE_TYPE

  • MPICH_BCAST_TREE_TYPE

• Description: - Tree type for tree based bcast kary - kary tree type

  • knomial_1 - knomial_1 tree type knomial_2 - knomial_2 tree type

  • topology_aware - topology_aware tree type topology_aware_k -

  • topology_aware tree type with branching factor k topology_wave -

  • topology_wave tree type

• Default: “kary”

MPIR_CVAR_BCAST_TOPO_REORDER_ENABLE

• Aliases: - MVP_BCAST_TOPO_REORDER_ENABLE

  • MPICH_BCAST_TOPO_REORDER_ENABLE

• Description: - This cvar controls if the leaders are reordered based on

  • the number of ranks in each group.

• Default: 1

MPIR_CVAR_BCAST_TOPO_OVERHEAD

• Aliases: - MVP_BCAST_TOPO_OVERHEAD

  • MPICH_BCAST_TOPO_OVERHEAD

• Description: - This cvar controls the size of the overhead.

• Default: 200

MPIR_CVAR_BCAST_TOPO_DIFF_GROUPS

• Aliases: - MVP_BCAST_TOPO_DIFF_GROUPS

  • MPICH_BCAST_TOPO_DIFF_GROUPS

• Description: - This cvar controls the latency between different groups.

• Default: 2800

MPIR_CVAR_BCAST_TOPO_DIFF_SWITCHES

• Aliases: - MVP_BCAST_TOPO_DIFF_SWITCHES

  • MPICH_BCAST_TOPO_DIFF_SWITCHES

• Description: - This cvar controls the latency between different switches

  • in the same groups.

• Default: 1900

MPIR_CVAR_BCAST_TOPO_SAME_SWITCHES

• Aliases: - MVP_BCAST_TOPO_SAME_SWITCHES

  • MPICH_BCAST_TOPO_SAME_SWITCHES

• Description: - This cvar controls the latency in the same switch.

• Default: 1600

MPIR_CVAR_BCAST_IS_NON_BLOCKING

• Aliases: - MVP_BCAST_IS_NON_BLOCKING

  • MPICH_BCAST_IS_NON_BLOCKING

• Description: - If set to true, MPI_Bcast will use non-blocking send.

• Default: 1

MPIR_CVAR_BCAST_TREE_PIPELINE_CHUNK_SIZE

• Aliases: - MVP_BCAST_TREE_PIPELINE_CHUNK_SIZE

  • MPICH_BCAST_TREE_PIPELINE_CHUNK_SIZE

• Description: - Indicates the chunk size for pipelined bcast.

• Default: 8192

MPIR_CVAR_BCAST_RECV_PRE_POST

• Aliases: - MVP_BCAST_RECV_PRE_POST

  • MPICH_BCAST_RECV_PRE_POST

• Description: - If set to true, MPI_Bcast will pre-post all the receives.

• Default: 0

MPIR_CVAR_BCAST_INTER_ALGORITHM

• Aliases: - MVP_BCAST_INTER_ALGORITHM

  • MPICH_BCAST_INTER_ALGORITHM

• Description: - Variable to select bcast algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • remote_send_local_bcast - Force remote-send-local-bcast algorithm

• Default: MPIR_CVAR_BCAST_INTER_ALGORITHM_auto

MPIR_CVAR_IBCAST_TREE_KVAL

• Aliases: - MVP_IBCAST_TREE_KVAL

  • MPICH_IBCAST_TREE_KVAL

• Description: - k value for tree (kary, knomial, etc.) based ibcast

• Default: 2

MPIR_CVAR_IBCAST_TREE_TYPE

• Aliases: - MVP_IBCAST_TREE_TYPE

  • MPICH_IBCAST_TREE_TYPE

• Description: - Tree type for tree based ibcast kary - kary tree type

  • knomial_1 - knomial_1 tree type knomial_2 - knomial_2 tree type

• Default: “kary”

MPIR_CVAR_IBCAST_TREE_PIPELINE_CHUNK_SIZE

• Aliases: - MVP_IBCAST_TREE_PIPELINE_CHUNK_SIZE

  • MPICH_IBCAST_TREE_PIPELINE_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in tree based

  • ibcast. Default value is 0, that is, no pipelining by default

• Default: 0

MPIR_CVAR_IBCAST_RING_CHUNK_SIZE

• Aliases: - MVP_IBCAST_RING_CHUNK_SIZE

  • MPICH_IBCAST_RING_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in ibcast

  • ring algorithm. Default value is 0, that is, no pipelining by

  • default

• Default: 0

MPIR_CVAR_IBCAST_INTRA_ALGORITHM

• Aliases: - MVP_IBCAST_INTRA_ALGORITHM

  • MPICH_IBCAST_INTRA_ALGORITHM

• Description: - Variable to select ibcast algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_binomial - - - - Force Binomial

  • algorithm

  • sched_smp - - - - - Force smp algorithm

  • sched_scatter_recursive_doubling_allgather - Force Scatter

  • Recursive Doubling Allgather algorithm

  • sched_scatter_ring_allgather - - Force Scatter Ring

  • Allgather algorithm

  • tsp_tree - - - - Force Generic Transport

  • Tree algorithm

  • tsp_scatterv_recexch_allgatherv - - Force Generic Transport

  • Scatterv followed by Recursive Exchange Allgatherv algorithm

  • tsp_scatterv_ring_allgatherv - - Force Generic Transport

  • Scatterv followed by Ring Allgatherv algorithm

  • tsp_ring - - - - Force Generic Transport

  • Ring algorithm

• Default: MPIR_CVAR_IBCAST_INTRA_ALGORITHM_auto

MPIR_CVAR_IBCAST_SCATTERV_KVAL

• Aliases: - MVP_IBCAST_SCATTERV_KVAL

  • MPICH_IBCAST_SCATTERV_KVAL

• Description: - k value for tree based scatter in

  • scatter_recexch_allgather algorithm

• Default: 2

MPIR_CVAR_IBCAST_ALLGATHERV_RECEXCH_KVAL

• Aliases: - MVP_IBCAST_ALLGATHERV_RECEXCH_KVAL

  • MPICH_IBCAST_ALLGATHERV_RECEXCH_KVAL

• Description: - k value for recursive exchange based allgather in

  • scatter_recexch_allgather algorithm

• Default: 2

MPIR_CVAR_IBCAST_INTER_ALGORITHM

• Aliases: - MVP_IBCAST_INTER_ALGORITHM

  • MPICH_IBCAST_INTER_ALGORITHM

• Description: - Variable to select ibcast algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_flat - Force flat algorithm

• Default: MPIR_CVAR_IBCAST_INTER_ALGORITHM_auto

MPIR_CVAR_GATHER_INTER_SHORT_MSG_SIZE

• Aliases: - MVP_GATHER_INTER_SHORT_MSG_SIZE

  • MPICH_GATHER_INTER_SHORT_MSG_SIZE

• Description: - use the short message algorithm for intercommunicator

  • MPI_Gather if the send buffer size is < this value (in bytes) (See

  • also: MPIR_CVAR_GATHER_VSMALL_MSG_SIZE)

• Default: 2048

MPIR_CVAR_GATHER_INTRA_ALGORITHM

• Aliases: - MVP_GATHER_INTRA_ALGORITHM

  • MPICH_GATHER_INTRA_ALGORITHM

• Description: - Variable to select gather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • binomial - Force binomial algorithm

  • nb - Force nonblocking algorithm

  • osu_direct - Force OSU direct algorithm

  • osu_direct_block - Force OSU direct block algorithm

• Default: MPIR_CVAR_GATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_GATHER_INTER_ALGORITHM

• Aliases: - MVP_GATHER_INTER_ALGORITHM

  • MPICH_GATHER_INTER_ALGORITHM

• Description: - Variable to select gather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - - - Force linear algorithm

  • local_gather_remote_send - Force local-gather-remote-send algorithm

  • nb - - - Force nonblocking algorithm

• Default: MPIR_CVAR_GATHER_INTER_ALGORITHM_auto

MPIR_CVAR_IGATHER_INTRA_ALGORITHM

• Aliases: - MVP_IGATHER_INTRA_ALGORITHM

  • MPICH_IGATHER_INTRA_ALGORITHM

• Description: - Variable to select igather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_binomial - Force binomial algorithm

  • tsp_tree - Force genetric transport based tree algorithm

• Default: MPIR_CVAR_IGATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_IGATHER_TREE_KVAL

• Aliases: - MVP_IGATHER_TREE_KVAL

  • MPICH_IGATHER_TREE_KVAL

• Description: - k value for tree based igather

• Default: 2

MPIR_CVAR_IGATHER_INTER_ALGORITHM

• Aliases: - MVP_IGATHER_INTER_ALGORITHM

  • MPICH_IGATHER_INTER_ALGORITHM

• Description: - Variable to select igather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_long - Force long inter algorithm

  • sched_short - Force short inter algorithm

• Default: MPIR_CVAR_IGATHER_INTER_ALGORITHM_auto

MPIR_CVAR_GATHERV_INTRA_ALGORITHM

• Aliases: - MVP_GATHERV_INTRA_ALGORITHM

  • MPICH_GATHERV_INTRA_ALGORITHM

• Description: - Variable to select gatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - Force linear algorithm

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_GATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_GATHERV_INTER_ALGORITHM

• Aliases: - MVP_GATHERV_INTER_ALGORITHM

  • MPICH_GATHERV_INTER_ALGORITHM

• Description: - Variable to select gatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - Force linear algorithm

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_GATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_IGATHERV_INTRA_ALGORITHM

• Aliases: - MVP_IGATHERV_INTRA_ALGORITHM

  • MPICH_IGATHERV_INTRA_ALGORITHM

• Description: - Variable to select igatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_IGATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_IGATHERV_INTER_ALGORITHM

• Aliases: - MVP_IGATHERV_INTER_ALGORITHM

  • MPICH_IGATHERV_INTER_ALGORITHM

• Description: - Variable to select igatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_IGATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_SCATTER_INTER_SHORT_MSG_SIZE

• Aliases: - MVP_SCATTER_INTER_SHORT_MSG_SIZE

  • MPICH_SCATTER_INTER_SHORT_MSG_SIZE

• Description: - use the short message algorithm for intercommunicator

  • MPI_Scatter if the send buffer size is < this value (in bytes)

• Default: 2048

MPIR_CVAR_SCATTER_INTRA_ALGORITHM

• Aliases: - MVP_SCATTER_INTRA_ALGORITHM

  • MPICH_SCATTER_INTRA_ALGORITHM

• Description: - Variable to select scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • binomial - Force binomial algorithm

  • nb - Force nonblocking algorithm

  • osu_direct - Force OSU direct alogirthm

• Default: MPIR_CVAR_SCATTER_INTRA_ALGORITHM_auto

MPIR_CVAR_SCATTER_INTER_ALGORITHM

• Aliases: - MVP_SCATTER_INTER_ALGORITHM

  • MPICH_SCATTER_INTER_ALGORITHM

• Description: - Variable to select scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - - - Force linear algorithm

  • nb - - - - Force nonblocking algorithm

  • remote_send_local_scatter - Force remote-send-local-scatter

  • algorithm

• Default: MPIR_CVAR_SCATTER_INTER_ALGORITHM_auto

MPIR_CVAR_ISCATTER_INTRA_ALGORITHM

• Aliases: - MVP_ISCATTER_INTRA_ALGORITHM

  • MPICH_ISCATTER_INTRA_ALGORITHM

• Description: - Variable to select iscatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_binomial - Force binomial algorithm

  • tsp_tree - Force genetric transport based tree algorithm

• Default: MPIR_CVAR_ISCATTER_INTRA_ALGORITHM_auto

MPIR_CVAR_ISCATTER_TREE_KVAL

• Aliases: - MVP_ISCATTER_TREE_KVAL

  • MPICH_ISCATTER_TREE_KVAL

• Description: - k value for tree based iscatter

• Default: 2

MPIR_CVAR_ISCATTER_INTER_ALGORITHM

• Aliases: - MVP_ISCATTER_INTER_ALGORITHM

  • MPICH_ISCATTER_INTER_ALGORITHM

• Description: - Variable to select iscatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - - Force linear algorithm

  • sched_remote_send_local_scatter - Force remote-send-local-scatter

  • algorithm

• Default: MPIR_CVAR_ISCATTER_INTER_ALGORITHM_auto

MPIR_CVAR_SCATTERV_INTRA_ALGORITHM

• Aliases: - MVP_SCATTERV_INTRA_ALGORITHM

  • MPICH_SCATTERV_INTRA_ALGORITHM

• Description: - Variable to select scatterv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - Force linear algorithm

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_SCATTERV_INTRA_ALGORITHM_auto

MPIR_CVAR_SCATTERV_INTER_ALGORITHM

• Aliases: - MVP_SCATTERV_INTER_ALGORITHM

  • MPICH_SCATTERV_INTER_ALGORITHM

• Description: - Variable to select scatterv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • linear - Force linear algorithm

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_SCATTERV_INTER_ALGORITHM_auto

MPIR_CVAR_ISCATTERV_INTRA_ALGORITHM

• Aliases: - MVP_ISCATTERV_INTRA_ALGORITHM

  • MPICH_ISCATTERV_INTRA_ALGORITHM

• Description: - Variable to select iscatterv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_ISCATTERV_INTRA_ALGORITHM_auto

MPIR_CVAR_ISCATTERV_INTER_ALGORITHM

• Aliases: - MVP_ISCATTERV_INTER_ALGORITHM

  • MPICH_ISCATTERV_INTER_ALGORITHM

• Description: - Variable to select iscatterv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_ISCATTERV_INTER_ALGORITHM_auto

MPIR_CVAR_ALLGATHER_SHORT_MSG_SIZE

• Aliases: - MVP_ALLGATHER_SHORT_MSG_SIZE

  • MPICH_ALLGATHER_SHORT_MSG_SIZE

• Description: - For MPI_Allgather and MPI_Allgatherv, the short message

  • algorithm will be used if the send buffer size is < this value (in

  • bytes). (See also: MPIR_CVAR_ALLGATHER_LONG_MSG_SIZE)

• Default: 81920

MPIR_CVAR_ALLGATHER_LONG_MSG_SIZE

• Aliases: - MVP_ALLGATHER_LONG_MSG_SIZE

  • MPICH_ALLGATHER_LONG_MSG_SIZE

• Description: - For MPI_Allgather and MPI_Allgatherv, the long message

  • algorithm will be used if the send buffer size is >= this value (in

  • bytes) (See also: MPIR_CVAR_ALLGATHER_SHORT_MSG_SIZE)

• Default: 524288

MPIR_CVAR_ALLGATHER_INTRA_ALGORITHM

• Aliases: - MVP_ALLGATHER_INTRA_ALGORITHM

  • MPICH_ALLGATHER_INTRA_ALGORITHM

• Description: - Variable to select allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • brucks - - Force brucks algorithm

  • k_brucks - - Force brucks algorithm

  • nb - - - Force nonblocking algorithm

  • recursive_doubling - Force recursive doubling algorithm

  • ring - - Force ring algorithm

  • recexch_doubling - Force recexch distance doubling algorithm

  • recexch_halving - Force recexch distance halving algorithm

  • osu_direct - - Force MVAPICH direct algorithm

  • osu_direct_spread - Force MVAPICH direct spread algorithm

  • osu_gather_bcast - Force MVAPICH gather-bcast algorithm

• Default: MPIR_CVAR_ALLGATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLGATHER_BRUCKS_KVAL

• Aliases: - MVP_ALLGATHER_BRUCKS_KVAL

  • MPICH_ALLGATHER_BRUCKS_KVAL

• Description: - radix (k) value for generic transport brucks based

  • allgather

• Default: 2

MPIR_CVAR_ALLGATHER_RECEXCH_KVAL

• Aliases: - MVP_ALLGATHER_RECEXCH_KVAL

  • MPICH_ALLGATHER_RECEXCH_KVAL

• Description: - k value for recursive exchange based allgather

• Default: 2

MPIR_CVAR_ALLGATHER_RECEXCH_SINGLE_PHASE_RECV

• Aliases: - MVP_ALLGATHER_RECEXCH_SINGLE_PHASE_RECV

  • MPICH_ALLGATHER_RECEXCH_SINGLE_PHASE_RECV

• Description: - This CVAR controls whether the recv is posted for one

  • phase or two phases in recexch algos. By default, we post the recvs

  • for 2 phases.

• Default: 0

MPIR_CVAR_ALLGATHER_INTER_ALGORITHM

• Aliases: - MVP_ALLGATHER_INTER_ALGORITHM

  • MPICH_ALLGATHER_INTER_ALGORITHM

• Description: - Variable to select allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • local_gather_remote_bcast - Force local-gather-remote-bcast

  • algorithm

  • nb - - - - Force nonblocking algorithm

• Default: MPIR_CVAR_ALLGATHER_INTER_ALGORITHM_auto

MPIR_CVAR_IALLGATHER_RECEXCH_KVAL

• Aliases: - MVP_IALLGATHER_RECEXCH_KVAL

  • MPICH_IALLGATHER_RECEXCH_KVAL

• Description: - k value for recursive exchange based iallgather

• Default: 2

MPIR_CVAR_IALLGATHER_BRUCKS_KVAL

• Aliases: - MVP_IALLGATHER_BRUCKS_KVAL

  • MPICH_IALLGATHER_BRUCKS_KVAL

• Description: - k value for radix in brucks based iallgather

• Default: 2

MPIR_CVAR_IALLGATHER_INTRA_ALGORITHM

• Aliases: - MVP_IALLGATHER_INTRA_ALGORITHM

  • MPICH_IALLGATHER_INTRA_ALGORITHM

• Description: - Variable to select iallgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_ring - - Force ring algorithm

  • sched_brucks - - Force brucks algorithm

  • sched_recursive_doubling - Force recursive doubling algorithm

  • tsp_ring - Force generic transport ring algorithm

  • tsp_brucks - Force generic transport based brucks algorithm

  • tsp_recexch_doubling - Force generic transport recursive exchange

  • with neighbours doubling in distance in each phase

  • tsp_recexch_halving - Force generic transport recursive exchange

  • with neighbours halving in distance in each phase

• Default: MPIR_CVAR_IALLGATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLGATHER_INTER_ALGORITHM

• Aliases: - MVP_IALLGATHER_INTER_ALGORITHM

  • MPICH_IALLGATHER_INTER_ALGORITHM

• Description: - Variable to select iallgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_local_gather_remote_bcast - Force local-gather-remote-bcast

  • algorithm

• Default: MPIR_CVAR_IALLGATHER_INTER_ALGORITHM_auto

MPIR_CVAR_ALLGATHERV_PIPELINE_MSG_SIZE

• Aliases: - MVP_ALLGATHERV_PIPELINE_MSG_SIZE

  • MPICH_ALLGATHERV_PIPELINE_MSG_SIZE

• Description: - The smallest message size that will be used for the

  • pipelined, large-message, ring algorithm in the MPI_Allgatherv

  • implementation.

• Default: 32768

MPIR_CVAR_ALLGATHERV_INTRA_ALGORITHM

• Aliases: - MVP_ALLGATHERV_INTRA_ALGORITHM

  • MPICH_ALLGATHERV_INTRA_ALGORITHM

• Description: - Variable to select allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • brucks - - Force brucks algorithm

  • nb - - - Force nonblocking algorithm

  • recursive_doubling - Force recursive doubling algorithm

  • ring - - Force ring algorithm

• Default: MPIR_CVAR_ALLGATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLGATHERV_INTER_ALGORITHM

• Aliases: - MVP_ALLGATHERV_INTER_ALGORITHM

  • MPICH_ALLGATHERV_INTER_ALGORITHM

• Description: - Variable to select allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - - Force nonblocking algorithm

  • remote_gather_local_bcast - Force remote-gather-local-bcast

  • algorithm

• Default: MPIR_CVAR_ALLGATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_IALLGATHERV_RECEXCH_KVAL

• Aliases: - MVP_IALLGATHERV_RECEXCH_KVAL

  • MPICH_IALLGATHERV_RECEXCH_KVAL

• Description: - k value for recursive exchange based iallgatherv

• Default: 2

MPIR_CVAR_IALLGATHERV_BRUCKS_KVAL

• Aliases: - MVP_IALLGATHERV_BRUCKS_KVAL

  • MPICH_IALLGATHERV_BRUCKS_KVAL

• Description: - k value for radix in brucks based iallgatherv

• Default: 2

MPIR_CVAR_IALLGATHERV_INTRA_ALGORITHM

• Aliases: - MVP_IALLGATHERV_INTRA_ALGORITHM

  • MPICH_IALLGATHERV_INTRA_ALGORITHM

• Description: - Variable to select iallgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_brucks - - Force brucks algorithm

  • sched_recursive_doubling - Force recursive doubling algorithm

  • sched_ring - - Force ring algorithm

  • tsp_recexch_doubling - Force generic transport recursive exchange

  • with neighbours doubling in distance in each phase

  • tsp_recexch_halving - Force generic transport recursive exchange

  • with neighbours halving in distance in each phase

  • tsp_ring - - Force generic transport ring algorithm

  • tsp_brucks - - Force generic transport based brucks

  • algorithm

• Default: MPIR_CVAR_IALLGATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLGATHERV_INTER_ALGORITHM

• Aliases: - MVP_IALLGATHERV_INTER_ALGORITHM

  • MPICH_IALLGATHERV_INTER_ALGORITHM

• Description: - Variable to select iallgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_remote_gather_local_bcast - Force remote-gather-local-bcast

  • algorithm

• Default: MPIR_CVAR_IALLGATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_ALLTOALL_SHORT_MSG_SIZE

• Aliases: - MVP_ALLTOALL_SHORT_MSG_SIZE

  • MPICH_ALLTOALL_SHORT_MSG_SIZE

• Description: - the short message algorithm will be used if the

  • per-destination message size (sendcount*size(sendtype)) is <= this

  • value (See also: MPIR_CVAR_ALLTOALL_MEDIUM_MSG_SIZE)

• Default: 256

MPIR_CVAR_ALLTOALL_MEDIUM_MSG_SIZE

• Aliases: - MVP_ALLTOALL_MEDIUM_MSG_SIZE

  • MPICH_ALLTOALL_MEDIUM_MSG_SIZE

• Description: - the medium message algorithm will be used if the

  • per-destination message size (sendcount*size(sendtype)) is <= this

  • value and larger than MPIR_CVAR_ALLTOALL_SHORT_MSG_SIZE (See also:

  • MPIR_CVAR_ALLTOALL_SHORT_MSG_SIZE)

• Default: 32768

MPIR_CVAR_ALLTOALL_THROTTLE

• Aliases: - MVP_ALLTOALL_THROTTLE

  • MPICH_ALLTOALL_THROTTLE

• Description: - max no. of irecvs/isends posted at a time in some alltoall

  • algorithms. Setting it to 0 causes all irecvs/isends to be posted

  • at once

• Default: 32

MPIR_CVAR_ALLTOALL_INTRA_ALGORITHM

• Aliases: - MVP_ALLTOALL_INTRA_ALGORITHM

  • MPICH_ALLTOALL_INTRA_ALGORITHM

• Description: - Variable to select alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • brucks - - - Force brucks algorithm

  • k_brucks - - - Force Force radix k brucks algorithm

  • nb - - - - Force nonblocking algorithm

  • pairwise - - - Force pairwise algorithm

  • pairwise_sendrecv_replace - Force pairwise sendrecv replace

  • algorithm

  • scattered - - - Force scattered algorithm

• Default: MPIR_CVAR_ALLTOALL_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLTOALL_BRUCKS_KVAL

• Aliases: - MVP_ALLTOALL_BRUCKS_KVAL

  • MPICH_ALLTOALL_BRUCKS_KVAL

• Description: - radix (k) value for generic transport brucks based

  • alltoall

• Default: 2

MPIR_CVAR_ALLTOALL_INTER_ALGORITHM

• Aliases: - MVP_ALLTOALL_INTER_ALGORITHM

  • MPICH_ALLTOALL_INTER_ALGORITHM

• Description: - Variable to select alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • pairwise_exchange - Force pairwise exchange algorithm

• Default: MPIR_CVAR_ALLTOALL_INTER_ALGORITHM_auto

MPIR_CVAR_IALLTOALL_INTRA_ALGORITHM

• Aliases: - MVP_IALLTOALL_INTRA_ALGORITHM

  • MPICH_IALLTOALL_INTRA_ALGORITHM

• Description: - Variable to select ialltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_brucks - - Force brucks algorithm

  • sched_inplace - - Force inplace algorithm

  • sched_pairwise - - Force pairwise algorithm

  • sched_permuted_sendrecv - Force permuted sendrecv algorithm

  • tsp_ring - - Force generic transport based ring algorithm

  • tsp_brucks - - Force generic transport based brucks

  • algorithm

  • tsp_scattered - Force generic transport based scattered

  • algorithm

• Default: MPIR_CVAR_IALLTOALL_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLTOALL_INTER_ALGORITHM

• Aliases: - MVP_IALLTOALL_INTER_ALGORITHM

  • MPICH_IALLTOALL_INTER_ALGORITHM

• Description: - Variable to select ialltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_pairwise_exchange - Force pairwise exchange algorithm

• Default: MPIR_CVAR_IALLTOALL_INTER_ALGORITHM_auto

MPIR_CVAR_ALLTOALLV_INTRA_ALGORITHM

• Aliases: - MVP_ALLTOALLV_INTRA_ALGORITHM

  • MPICH_ALLTOALLV_INTRA_ALGORITHM

• Description: - Variable to select alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - - Force nonblocking algorithm

  • pairwise_sendrecv_replace - Force pairwise_sendrecv_replace

  • algorithm

  • scattered - - - Force scattered algorithm

• Default: MPIR_CVAR_ALLTOALLV_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLTOALLV_INTER_ALGORITHM

• Aliases: - MVP_ALLTOALLV_INTER_ALGORITHM

  • MPICH_ALLTOALLV_INTER_ALGORITHM

• Description: - Variable to select alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • pairwise_exchange - Force pairwise exchange algorithm

  • nb - - - Force nonblocking algorithm

• Default: MPIR_CVAR_ALLTOALLV_INTER_ALGORITHM_auto

MPIR_CVAR_IALLTOALLV_INTRA_ALGORITHM

• Aliases: - MVP_IALLTOALLV_INTRA_ALGORITHM

  • MPICH_IALLTOALLV_INTRA_ALGORITHM

• Description: - Variable to select ialltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_blocked - - Force blocked algorithm

  • sched_inplace - - Force inplace algorithm

  • tsp_scattered - Force generic transport based scattered

  • algorithm

  • tsp_blocked - - Force generic transport blocked algorithm

  • tsp_inplace - - Force generic transport inplace algorithm

• Default: MPIR_CVAR_IALLTOALLV_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLTOALLV_INTER_ALGORITHM

• Aliases: - MVP_IALLTOALLV_INTER_ALGORITHM

  • MPICH_IALLTOALLV_INTER_ALGORITHM

• Description: - Variable to select ialltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_pairwise_exchange - Force pairwise exchange algorithm

• Default: MPIR_CVAR_IALLTOALLV_INTER_ALGORITHM_auto

MPIR_CVAR_IALLTOALLV_SCATTERED_OUTSTANDING_TASKS

• Aliases: - MVP_IALLTOALLV_SCATTERED_OUTSTANDING_TASKS

  • MPICH_IALLTOALLV_SCATTERED_OUTSTANDING_TASKS

• Description: - Maximum number of outstanding sends and recvs posted at a

  • time

• Default: 64

MPIR_CVAR_IALLTOALLV_SCATTERED_BATCH_SIZE

• Aliases: - MVP_IALLTOALLV_SCATTERED_BATCH_SIZE

  • MPICH_IALLTOALLV_SCATTERED_BATCH_SIZE

• Description: - Number of send/receive tasks that scattered algorithm

  • waits for completion before posting another batch of send/receives

  • of that size

• Default: 4

MPIR_CVAR_ALLTOALLW_INTRA_ALGORITHM

• Aliases: - MVP_ALLTOALLW_INTRA_ALGORITHM

  • MPICH_ALLTOALLW_INTRA_ALGORITHM

• Description: - Variable to select alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - - Force nonblocking algorithm

  • pairwise_sendrecv_replace - Force pairwise sendrecv replace

  • algorithm

  • scattered - - - Force scattered algorithm

• Default: MPIR_CVAR_ALLTOALLW_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLTOALLW_INTER_ALGORITHM

• Aliases: - MVP_ALLTOALLW_INTER_ALGORITHM

  • MPICH_ALLTOALLW_INTER_ALGORITHM

• Description: - Variable to select alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • pairwise_exchange - Force pairwise exchange algorithm

• Default: MPIR_CVAR_ALLTOALLW_INTER_ALGORITHM_auto

MPIR_CVAR_IALLTOALLW_INTRA_ALGORITHM

• Aliases: - MVP_IALLTOALLW_INTRA_ALGORITHM

  • MPICH_IALLTOALLW_INTRA_ALGORITHM

• Description: - Variable to select ialltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_blocked - - Force blocked algorithm

  • sched_inplace - - Force inplace algorithm

  • tsp_blocked - Force generic transport based blocked algorithm

  • tsp_inplace - Force generic transport based inplace algorithm

• Default: MPIR_CVAR_IALLTOALLW_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLTOALLW_INTER_ALGORITHM

• Aliases: - MVP_IALLTOALLW_INTER_ALGORITHM

  • MPICH_IALLTOALLW_INTER_ALGORITHM

• Description: - Variable to select ialltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_pairwise_exchange - Force pairwise exchange algorithm

• Default: MPIR_CVAR_IALLTOALLW_INTER_ALGORITHM_auto

MPIR_CVAR_REDUCE_SHORT_MSG_SIZE

• Aliases: - MVP_REDUCE_SHORT_MSG_SIZE

  • MPICH_REDUCE_SHORT_MSG_SIZE

• Description: - the short message algorithm will be used if the send

  • buffer size is <= this value (in bytes)

• Default: 2048

MPIR_CVAR_MAX_SMP_REDUCE_MSG_SIZE

• Aliases: - MVP_MAX_SMP_REDUCE_MSG_SIZE

  • MPICH_MAX_SMP_REDUCE_MSG_SIZE

• Description: - Maximum message size for which SMP-aware reduce is used.

  • A value of ‘0’ uses SMP-aware reduce for all message sizes.

• Default: 0

MPIR_CVAR_REDUCE_INTRA_ALGORITHM

• Aliases: - MVP_REDUCE_INTRA_ALGORITHM

  • MPICH_REDUCE_INTRA_ALGORITHM

• Description: - Variable to select reduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • binomial - - Force binomial algorithm

  • nb - - - Force nonblocking algorithm

  • smp - - - Force smp algorithm

  • reduce_scatter_gather - Force reduce scatter gather algorithm

  • osu_knomial - - Force MVAPICH knomial algorithm

  • osu_allreduce - - Force MVAPICH allreduce algorithm

• Default: MPIR_CVAR_REDUCE_INTRA_ALGORITHM_auto

MPIR_CVAR_REDUCE_INTER_ALGORITHM

• Aliases: - MVP_REDUCE_INTER_ALGORITHM

  • MPICH_REDUCE_INTER_ALGORITHM

• Description: - Variable to select reduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • local_reduce_remote_send - Force local-reduce-remote-send algorithm

  • nb - - - Force nonblocking algorithm

• Default: MPIR_CVAR_REDUCE_INTER_ALGORITHM_auto

MPIR_CVAR_IREDUCE_TREE_KVAL

• Aliases: - MVP_IREDUCE_TREE_KVAL

  • MPICH_IREDUCE_TREE_KVAL

• Description: - k value for tree (kary, knomial, etc.) based ireduce

• Default: 2

MPIR_CVAR_IREDUCE_TREE_TYPE

• Aliases: - MVP_IREDUCE_TREE_TYPE

  • MPICH_IREDUCE_TREE_TYPE

• Description: - Tree type for tree based ireduce kary - kary tree

  • knomial_1 - knomial_1 tree knomial_2 - knomial_2 tree

  • topology_aware - topology_aware tree type topology_aware_k -

  • topology_aware tree type with branching factor k topology_wave -

  • topology_wave tree type

• Default: “kary”

MPIR_CVAR_IREDUCE_TOPO_REORDER_ENABLE

• Aliases: - MVP_IREDUCE_TOPO_REORDER_ENABLE

  • MPICH_IREDUCE_TOPO_REORDER_ENABLE

• Description: - This cvar controls if the leaders are reordered based on

  • the number of ranks in each group.

• Default: 1

MPIR_CVAR_IREDUCE_TOPO_OVERHEAD

• Aliases: - MVP_IREDUCE_TOPO_OVERHEAD

  • MPICH_IREDUCE_TOPO_OVERHEAD

• Description: - This cvar controls the size of the overhead.

• Default: 200

MPIR_CVAR_IREDUCE_TOPO_DIFF_GROUPS

• Aliases: - MVP_IREDUCE_TOPO_DIFF_GROUPS

  • MPICH_IREDUCE_TOPO_DIFF_GROUPS

• Description: - This cvar controls the latency between different groups.

• Default: 2800

MPIR_CVAR_IREDUCE_TOPO_DIFF_SWITCHES

• Aliases: - MVP_IREDUCE_TOPO_DIFF_SWITCHES

  • MPICH_IREDUCE_TOPO_DIFF_SWITCHES

• Description: - This cvar controls the latency between different switches

  • in the same groups.

• Default: 1900

MPIR_CVAR_IREDUCE_TOPO_SAME_SWITCHES

• Aliases: - MVP_IREDUCE_TOPO_SAME_SWITCHES

  • MPICH_IREDUCE_TOPO_SAME_SWITCHES

• Description: - This cvar controls the latency in the same switch.

• Default: 1600

MPIR_CVAR_IREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Aliases: - MVP_IREDUCE_TREE_PIPELINE_CHUNK_SIZE

  • MPICH_IREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in tree based

  • ireduce. Default value is 0, that is, no pipelining by default

• Default: -1

MPIR_CVAR_IREDUCE_RING_CHUNK_SIZE

• Aliases: - MVP_IREDUCE_RING_CHUNK_SIZE

  • MPICH_IREDUCE_RING_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in ireduce

  • ring algorithm. Default value is 0, that is, no pipelining by

  • default

• Default: 0

MPIR_CVAR_IREDUCE_TREE_BUFFER_PER_CHILD

• Aliases: - MVP_IREDUCE_TREE_BUFFER_PER_CHILD

  • MPICH_IREDUCE_TREE_BUFFER_PER_CHILD

• Description: - If set to true, a rank in tree algorithms will allocate a

  • dedicated buffer for every child it receives data from. This would

  • mean more memory consumption but it would allow preposting of the

  • receives and hence reduce the number of unexpected messages. If set

  • to false, there is only one buffer that is used to receive the data

  • from all the children. The receives are therefore serialized, that

  • is, only one receive can be posted at a time.

• Default: 0

MPIR_CVAR_IREDUCE_INTRA_ALGORITHM

• Aliases: - MVP_IREDUCE_INTRA_ALGORITHM

  • MPICH_IREDUCE_INTRA_ALGORITHM

• Description: - Variable to select ireduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_smp - - - Force smp algorithm

  • sched_binomial - - Force binomial algorithm

  • sched_reduce_scatter_gather - Force reduce scatter gather algorithm

  • tsp_tree - - - Force Generic Transport Tree

  • tsp_ring - - - Force Generic Transport Ring

• Default: MPIR_CVAR_IREDUCE_INTRA_ALGORITHM_auto

MPIR_CVAR_IREDUCE_INTER_ALGORITHM

• Aliases: - MVP_IREDUCE_INTER_ALGORITHM

  • MPICH_IREDUCE_INTER_ALGORITHM

• Description: - Variable to select ireduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_local_reduce_remote_send - Force local-reduce-remote-send

  • algorithm

• Default: MPIR_CVAR_IREDUCE_INTER_ALGORITHM_auto

MPIR_CVAR_ALLREDUCE_SHORT_MSG_SIZE

• Aliases: - MVP_ALLREDUCE_SHORT_MSG_SIZE

  • MPICH_ALLREDUCE_SHORT_MSG_SIZE

• Description: - the short message algorithm will be used if the send

  • buffer size is <= this value (in bytes)

• Default: 2048

MPIR_CVAR_MAX_SMP_ALLREDUCE_MSG_SIZE

• Aliases: - MVP_MAX_SMP_ALLREDUCE_MSG_SIZE

  • MPICH_MAX_SMP_ALLREDUCE_MSG_SIZE

• Description: - Maximum message size for which SMP-aware allreduce is

  • used. A value of ‘0’ uses SMP-aware allreduce for all message

  • sizes.

• Default: 0

MPIR_CVAR_ALLREDUCE_INTRA_ALGORITHM

• Aliases: - MVP_ALLREDUCE_INTRA_ALGORITHM

  • MPICH_ALLREDUCE_INTRA_ALGORITHM

• Description: - Variable to select allreduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • smp - - - Force smp algorithm

  • recursive_doubling - Force recursive doubling algorithm

  • recursive_multiplying - Force recursive multiplying algorithm

  • reduce_scatter_allgather - Force reduce scatter allgather algorithm

  • tree - - - Force pipelined tree algorithm

  • recexch - - - Force generic transport recursive

  • exchange algorithm

  • ring - - - Force ring algorithm

  • k_reduce_scatter_allgather - Force reduce scatter allgather

  • algorithm

  • mvapich_tuned - - Use MVAPICH autotuning

  • osu_mcast - - - Force osu mcast based design

  • osu_sharp - - - Force osu sharp design

• Default: MPIR_CVAR_ALLREDUCE_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLREDUCE_RECURSIVE_MULTIPLYING_KVAL

• Aliases: - MVP_ALLREDUCE_RECURSIVE_MULTIPLYING_KVAL

  • MPICH_ALLREDUCE_RECURSIVE_MULTIPLYING_KVAL

• Description: - radix value (power of k) for generic recursive multiplying

  • based allreduce

• Default: 2

MPIR_CVAR_ALLREDUCE_TREE_TYPE

• Aliases: - MVP_ALLREDUCE_TREE_TYPE

  • MPICH_ALLREDUCE_TREE_TYPE

• Description: - Tree type for tree based allreduce knomial_1 is default as

  • it supports both commutative and non-commutative reduce operations

  • kary - kary tree type knomial_1 - knomial_1 tree type (tree

  • grows starting from the left of the root) knomial_2 - knomial_2

  • tree type (tree grows starting from the right of the root)

  • topology_aware - topology_aware tree type topology_aware_k -

  • topology_aware tree type with branching factor k topology_wave -

  • topology_wave tree type

• Default: “knomial_1”

MPIR_CVAR_ALLREDUCE_TREE_KVAL

• Aliases: - MVP_ALLREDUCE_TREE_KVAL

  • MPICH_ALLREDUCE_TREE_KVAL

• Description: - Indicates the branching factor for kary or knomial trees.

• Default: 2

MPIR_CVAR_ALLREDUCE_TOPO_REORDER_ENABLE

• Aliases: - MVP_ALLREDUCE_TOPO_REORDER_ENABLE

  • MPICH_ALLREDUCE_TOPO_REORDER_ENABLE

• Description: - This cvar controls if the leaders are reordered based on

  • the number of ranks in each group.

• Default: 1

MPIR_CVAR_ALLREDUCE_TOPO_OVERHEAD

• Aliases: - MVP_ALLREDUCE_TOPO_OVERHEAD

  • MPICH_ALLREDUCE_TOPO_OVERHEAD

• Description: - This cvar controls the size of the overhead.

• Default: 200

MPIR_CVAR_ALLREDUCE_TOPO_DIFF_GROUPS

• Aliases: - MVP_ALLREDUCE_TOPO_DIFF_GROUPS

  • MPICH_ALLREDUCE_TOPO_DIFF_GROUPS

• Description: - This cvar controls the latency between different groups.

• Default: 2800

MPIR_CVAR_ALLREDUCE_TOPO_DIFF_SWITCHES

• Aliases: - MVP_ALLREDUCE_TOPO_DIFF_SWITCHES

  • MPICH_ALLREDUCE_TOPO_DIFF_SWITCHES

• Description: - This cvar controls the latency between different switches

  • in the same groups.

• Default: 1900

MPIR_CVAR_ALLREDUCE_TOPO_SAME_SWITCHES

• Aliases: - MVP_ALLREDUCE_TOPO_SAME_SWITCHES

  • MPICH_ALLREDUCE_TOPO_SAME_SWITCHES

• Description: - This cvar controls the latency in the same switch.

• Default: 1600

MPIR_CVAR_ALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Aliases: - MVP_ALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

  • MPICH_ALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in tree based

  • allreduce. Default value is 0, that is, no pipelining by default

• Default: 0

MPIR_CVAR_ALLREDUCE_TREE_BUFFER_PER_CHILD

• Aliases: - MVP_ALLREDUCE_TREE_BUFFER_PER_CHILD

  • MPICH_ALLREDUCE_TREE_BUFFER_PER_CHILD

• Description: - If set to true, a rank in tree_kary and tree_knomial

  • algorithms will allocate a dedicated buffer for every child it

  • receives data from. This would mean more memory consumption but it

  • would allow preposting of the receives and hence reduce the number

  • of unexpected messages. If set to false, there is only one buffer

  • that is used to receive the data from all the children. The

  • receives are therefore serialized, that is, only one receive can be

  • posted at a time.

• Default: 0

MPIR_CVAR_ALLREDUCE_RECEXCH_KVAL

• Aliases: - MVP_ALLREDUCE_RECEXCH_KVAL

  • MPICH_ALLREDUCE_RECEXCH_KVAL

• Description: - k value for recursive exchange based allreduce

• Default: 2

MPIR_CVAR_ALLREDUCE_RECEXCH_SINGLE_PHASE_RECV

• Aliases: - MVP_ALLREDUCE_RECEXCH_SINGLE_PHASE_RECV

  • MPICH_ALLREDUCE_RECEXCH_SINGLE_PHASE_RECV

• Description: - This CVAR controls whether the recv is posted for one

  • phase or two phases in recexch algos. By default, we post the recvs

  • for 2 phases.

• Default: 0

MPIR_CVAR_ALLREDUCE_INTER_ALGORITHM

• Aliases: - MVP_ALLREDUCE_INTER_ALGORITHM

  • MPICH_ALLREDUCE_INTER_ALGORITHM

• Description: - Variable to select allreduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • reduce_exchange_bcast - Force reduce-exchange-bcast algorithm

• Default: MPIR_CVAR_ALLREDUCE_INTER_ALGORITHM_auto

MPIR_CVAR_IALLREDUCE_TREE_KVAL

• Aliases: - MVP_IALLREDUCE_TREE_KVAL

  • MPICH_IALLREDUCE_TREE_KVAL

• Description: - k value for tree based iallreduce (for tree_kary and

  • tree_knomial)

• Default: 2

MPIR_CVAR_IALLREDUCE_TREE_TYPE

• Aliases: - MVP_IALLREDUCE_TREE_TYPE

  • MPICH_IALLREDUCE_TREE_TYPE

• Description: - Tree type for tree based ibcast kary - kary tree type

  • knomial_1 - knomial_1 tree type knomial_2 - knomial_2 tree type

• Default: “kary”

MPIR_CVAR_IALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Aliases: - MVP_IALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

  • MPICH_IALLREDUCE_TREE_PIPELINE_CHUNK_SIZE

• Description: - Maximum chunk size (in bytes) for pipelining in tree based

  • iallreduce. Default value is 0, that is, no pipelining by default

• Default: 0

MPIR_CVAR_IALLREDUCE_TREE_BUFFER_PER_CHILD

• Aliases: - MVP_IALLREDUCE_TREE_BUFFER_PER_CHILD

  • MPICH_IALLREDUCE_TREE_BUFFER_PER_CHILD

• Description: - If set to true, a rank in tree_kary and tree_knomial

  • algorithms will allocate a dedicated buffer for every child it

  • receives data from. This would mean more memory consumption but it

  • would allow preposting of the receives and hence reduce the number

  • of unexpected messages. If set to false, there is only one buffer

  • that is used to receive the data from all the children. The

  • receives are therefore serialized, that is, only one receive can be

  • posted at a time.

• Default: 0

MPIR_CVAR_IALLREDUCE_RECEXCH_KVAL

• Aliases: - MVP_IALLREDUCE_RECEXCH_KVAL

  • MPICH_IALLREDUCE_RECEXCH_KVAL

• Description: - k value for recursive exchange based iallreduce

• Default: 2

MPIR_CVAR_IALLREDUCE_INTRA_ALGORITHM

• Aliases: - MVP_IALLREDUCE_INTRA_ALGORITHM

  • MPICH_IALLREDUCE_INTRA_ALGORITHM

• Description: - Variable to select iallreduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_naive - - - Force naive algorithm

  • sched_smp - - - - Force smp algorithm

  • sched_recursive_doubling - - Force recursive doubling

  • algorithm

  • sched_reduce_scatter_allgather - Force reduce scatter allgather

  • algorithm

  • tsp_recexch_single_buffer - Force generic transport recursive

  • exchange with single buffer for receives

  • tsp_recexch_multiple_buffer - Force generic transport recursive

  • exchange with multiple buffers for receives

  • tsp_tree - - - Force generic transport tree

  • algorithm

  • tsp_ring - - - Force generic transport ring

  • algorithm

  • tsp_recexch_reduce_scatter_recexch_allgatherv - Force generic

  • transport recursive exchange with reduce scatter and allgatherv

• Default: MPIR_CVAR_IALLREDUCE_INTRA_ALGORITHM_auto

MPIR_CVAR_IALLREDUCE_INTER_ALGORITHM

• Aliases: - MVP_IALLREDUCE_INTER_ALGORITHM

  • MPICH_IALLREDUCE_INTER_ALGORITHM

• Description: - Variable to select iallreduce algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_remote_reduce_local_bcast - Force remote-reduce-local-bcast

  • algorithm

• Default: MPIR_CVAR_IALLREDUCE_INTER_ALGORITHM_auto

MPIR_CVAR_REDUCE_SCATTER_COMMUTATIVE_LONG_MSG_SIZE

• Aliases: - MVP_REDUCE_SCATTER_COMMUTATIVE_LONG_MSG_SIZE

  • MPICH_REDUCE_SCATTER_COMMUTATIVE_LONG_MSG_SIZE

• Description: - the long message algorithm will be used if the operation

  • is commutative and the send buffer size is >= this value (in bytes)

• Default: 524288

MPIR_CVAR_REDUCE_SCATTER_INTRA_ALGORITHM

• Aliases: - MVP_REDUCE_SCATTER_INTRA_ALGORITHM

  • MPICH_REDUCE_SCATTER_INTRA_ALGORITHM

• Description: - Variable to select reduce_scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • noncommutative - Force noncommutative algorithm

  • pairwise - - Force pairwise algorithm

  • recursive_doubling - Force recursive doubling algorithm

  • recursive_halving - Force recursive halving algorithm

  • osu_basic - - Force MVAPICH basic algorithm

  • osu_ring - - Force MVAPICH ring algorithm

• Default: MPIR_CVAR_REDUCE_SCATTER_INTRA_ALGORITHM_auto

MPIR_CVAR_REDUCE_SCATTER_INTER_ALGORITHM

• Aliases: - MVP_REDUCE_SCATTER_INTER_ALGORITHM

  • MPICH_REDUCE_SCATTER_INTER_ALGORITHM

• Description: - Variable to select reduce_scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - - Force nonblocking algorithm

  • remote_reduce_local_scatter - Force remote-reduce-local-scatter

  • algorithm

• Default: MPIR_CVAR_REDUCE_SCATTER_INTER_ALGORITHM_auto

MPIR_CVAR_IREDUCE_SCATTER_RECEXCH_KVAL

• Aliases: - MVP_IREDUCE_SCATTER_RECEXCH_KVAL

  • MPICH_IREDUCE_SCATTER_RECEXCH_KVAL

• Description: - k value for recursive exchange based ireduce_scatter

• Default: 2

MPIR_CVAR_IREDUCE_SCATTER_INTRA_ALGORITHM

• Aliases: - MVP_IREDUCE_SCATTER_INTRA_ALGORITHM

  • MPICH_IREDUCE_SCATTER_INTRA_ALGORITHM

• Description: - Variable to select ireduce_scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_noncommutative - Force noncommutative algorithm

  • sched_recursive_doubling - Force recursive doubling algorithm

  • sched_pairwise - - Force pairwise algorithm

  • sched_recursive_halving - Force recursive halving algorithm

  • tsp_recexch - - Force generic transport recursive exchange

  • algorithm

• Default: MPIR_CVAR_IREDUCE_SCATTER_INTRA_ALGORITHM_auto

MPIR_CVAR_IREDUCE_SCATTER_INTER_ALGORITHM

• Aliases: - MVP_IREDUCE_SCATTER_INTER_ALGORITHM

  • MPICH_IREDUCE_SCATTER_INTER_ALGORITHM

• Description: - Variable to select ireduce_scatter algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_remote_reduce_local_scatterv - Force

  • remote-reduce-local-scatterv algorithm

• Default: MPIR_CVAR_IREDUCE_SCATTER_INTER_ALGORITHM_auto

MPIR_CVAR_REDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

• Aliases: - MVP_REDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

  • MPICH_REDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

• Description: - Variable to select reduce_scatter_block algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • noncommutative - Force noncommutative algorithm

  • recursive_doubling - Force recursive doubling algorithm

  • pairwise - - Force pairwise algorithm

  • recursive_halving - Force recursive halving algorithm

  • nb - - - Force nonblocking algorithm

• Default: MPIR_CVAR_REDUCE_SCATTER_BLOCK_INTRA_ALGORITHM_auto

MPIR_CVAR_REDUCE_SCATTER_BLOCK_INTER_ALGORITHM

• Aliases: - MVP_REDUCE_SCATTER_BLOCK_INTER_ALGORITHM

  • MPICH_REDUCE_SCATTER_BLOCK_INTER_ALGORITHM

• Description: - Variable to select reduce_scatter_block algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - - Force nonblocking algorithm

  • remote_reduce_local_scatter - Force remote-reduce-local-scatter

  • algorithm

• Default: MPIR_CVAR_REDUCE_SCATTER_BLOCK_INTER_ALGORITHM_auto

MPIR_CVAR_IREDUCE_SCATTER_BLOCK_RECEXCH_KVAL

• Aliases: - MVP_IREDUCE_SCATTER_BLOCK_RECEXCH_KVAL

  • MPICH_IREDUCE_SCATTER_BLOCK_RECEXCH_KVAL

• Description: - k value for recursive exchange based ireduce_scatter_block

• Default: 2

MPIR_CVAR_IREDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

• Aliases: - MVP_IREDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

  • MPICH_IREDUCE_SCATTER_BLOCK_INTRA_ALGORITHM

• Description: - Variable to select ireduce_scatter_block algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_noncommutative - Force noncommutative algorithm

  • sched_recursive_doubling - Force recursive doubling algorithm

  • sched_pairwise - - Force pairwise algorithm

  • sched_recursive_halving - Force recursive halving algorithm

  • tsp_recexch - - Force generic transport recursive exchange

  • algorithm

• Default: MPIR_CVAR_IREDUCE_SCATTER_BLOCK_INTRA_ALGORITHM_auto

MPIR_CVAR_IREDUCE_SCATTER_BLOCK_INTER_ALGORITHM

• Aliases: - MVP_IREDUCE_SCATTER_BLOCK_INTER_ALGORITHM

  • MPICH_IREDUCE_SCATTER_BLOCK_INTER_ALGORITHM

• Description: - Variable to select ireduce_scatter_block algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_remote_reduce_local_scatterv - Force

  • remote-reduce-local-scatterv algorithm

• Default: MPIR_CVAR_IREDUCE_SCATTER_BLOCK_INTER_ALGORITHM_auto

MPIR_CVAR_SCAN_INTRA_ALGORITHM

• Aliases: - MVP_SCAN_INTRA_ALGORITHM

  • MPICH_SCAN_INTRA_ALGORITHM

• Description: - Variable to select allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • smp - - - Force smp algorithm

  • recursive_doubling - Force recursive doubling algorithm

• Default: MPIR_CVAR_SCAN_INTRA_ALGORITHM_auto

MPIR_CVAR_ISCAN_INTRA_ALGORITHM

• Aliases: - MVP_ISCAN_INTRA_ALGORITHM

  • MPICH_ISCAN_INTRA_ALGORITHM

• Description: - Variable to select allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_smp - - - Force smp algorithm

  • sched_recursive_doubling - Force recursive doubling algorithm

  • tsp_recursive_doubling - Force generic transport recursive doubling

  • algorithm

• Default: MPIR_CVAR_ISCAN_INTRA_ALGORITHM_auto

MPIR_CVAR_EXSCAN_INTRA_ALGORITHM

• Aliases: - MVP_EXSCAN_INTRA_ALGORITHM

  • MPICH_EXSCAN_INTRA_ALGORITHM

• Description: - Variable to select allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - - - Force nonblocking algorithm

  • recursive_doubling - Force recursive doubling algorithm

• Default: MPIR_CVAR_EXSCAN_INTRA_ALGORITHM_auto

MPIR_CVAR_IEXSCAN_INTRA_ALGORITHM

• Aliases: - MVP_IEXSCAN_INTRA_ALGORITHM

  • MPICH_IEXSCAN_INTRA_ALGORITHM

• Description: - Variable to select iexscan algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_recursive_doubling - Force recursive doubling algorithm

• Default: MPIR_CVAR_IEXSCAN_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLGATHER_INTRA_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLGATHER_INTRA_ALGORITHM

  • MPICH_NEIGHBOR_ALLGATHER_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLGATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLGATHER_INTER_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLGATHER_INTER_ALGORITHM

  • MPICH_NEIGHBOR_ALLGATHER_INTER_ALGORITHM

• Description: - Variable to select ineighbor_allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nonblocking algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLGATHER_INTER_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLGATHER_INTRA_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLGATHER_INTRA_ALGORITHM

  • MPICH_INEIGHBOR_ALLGATHER_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLGATHER_INTRA_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLGATHER_INTER_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLGATHER_INTER_ALGORITHM

  • MPICH_INEIGHBOR_ALLGATHER_INTER_ALGORITHM

• Description: - Variable to select ineighbor_allgather algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLGATHER_INTER_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

  • MPICH_NEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

• Description: - Variable to select neighbor_allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLGATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLGATHERV_INTER_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLGATHERV_INTER_ALGORITHM

  • MPICH_NEIGHBOR_ALLGATHERV_INTER_ALGORITHM

• Description: - Variable to select neighbor_allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLGATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

  • MPICH_INEIGHBOR_ALLGATHERV_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLGATHERV_INTRA_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLGATHERV_INTER_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLGATHERV_INTER_ALGORITHM

  • MPICH_INEIGHBOR_ALLGATHERV_INTER_ALGORITHM

• Description: - Variable to select ineighbor_allgatherv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLGATHERV_INTER_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALL_INTRA_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALL_INTRA_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALL_INTRA_ALGORITHM

• Description: - Variable to select neighbor_alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALL_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALL_INTER_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALL_INTER_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALL_INTER_ALGORITHM

• Description: - Variable to select neighbor_alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALL_INTER_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALL_INTRA_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALL_INTRA_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALL_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALL_INTRA_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALL_INTER_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALL_INTER_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALL_INTER_ALGORITHM

• Description: - Variable to select ineighbor_alltoall algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALL_INTER_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

• Description: - Variable to select neighbor_alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALLV_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALLV_INTER_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALLV_INTER_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALLV_INTER_ALGORITHM

• Description: - Variable to select neighbor_alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALLV_INTER_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALLV_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALLV_INTRA_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALLV_INTER_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALLV_INTER_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALLV_INTER_ALGORITHM

• Description: - Variable to select ineighbor_alltoallv algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALLV_INTER_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

• Description: - Variable to select neighbor_alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALLW_INTRA_ALGORITHM_auto

MPIR_CVAR_NEIGHBOR_ALLTOALLW_INTER_ALGORITHM

• Aliases: - MVP_NEIGHBOR_ALLTOALLW_INTER_ALGORITHM

  • MPICH_NEIGHBOR_ALLTOALLW_INTER_ALGORITHM

• Description: - Variable to select neighbor_alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • nb - Force nb algorithm

• Default: MPIR_CVAR_NEIGHBOR_ALLTOALLW_INTER_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALLW_INTRA_ALGORITHM

• Description: - Variable to select ineighbor_alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALLW_INTRA_ALGORITHM_auto

MPIR_CVAR_INEIGHBOR_ALLTOALLW_INTER_ALGORITHM

• Aliases: - MVP_INEIGHBOR_ALLTOALLW_INTER_ALGORITHM

  • MPICH_INEIGHBOR_ALLTOALLW_INTER_ALGORITHM

• Description: - Variable to select ineighbor_alltoallw algorithm

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE)

  • sched_auto - Internal algorithm selection for sched-based

  • algorithms

  • sched_linear - - Force linear algorithm

  • tsp_linear - - Force generic transport based linear algorithm

• Default: MPIR_CVAR_INEIGHBOR_ALLTOALLW_INTER_ALGORITHM_auto

MPIR_CVAR_BARRIER_DEVICE_COLLECTIVE

• Aliases: - MVP_BARRIER_DEVICE_COLLECTIVE

  • MPICH_BARRIER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Barrier will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IBARRIER_DEVICE_COLLECTIVE

• Aliases: - MVP_IBARRIER_DEVICE_COLLECTIVE

  • MPICH_IBARRIER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ibarrier will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_BARRIER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_BARRIER_INIT_DEVICE_COLLECTIVE

  • MPICH_BARRIER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Barrier will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_BCAST_DEVICE_COLLECTIVE

• Aliases: - MVP_BCAST_DEVICE_COLLECTIVE

  • MPICH_BCAST_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Bcast will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IBCAST_DEVICE_COLLECTIVE

• Aliases: - MVP_IBCAST_DEVICE_COLLECTIVE

  • MPICH_IBCAST_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ibcast will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_BCAST_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_BCAST_INIT_DEVICE_COLLECTIVE

  • MPICH_BCAST_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Bcast_init will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_GATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_GATHER_DEVICE_COLLECTIVE

  • MPICH_GATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Gather will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IGATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_IGATHER_DEVICE_COLLECTIVE

  • MPICH_IGATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Igather will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_GATHER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_GATHER_INIT_DEVICE_COLLECTIVE

  • MPICH_GATHER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Gather_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_GATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_GATHERV_DEVICE_COLLECTIVE

  • MPICH_GATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Gatherv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IGATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_IGATHERV_DEVICE_COLLECTIVE

  • MPICH_IGATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Igatherv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_GATHERV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_GATHERV_INIT_DEVICE_COLLECTIVE

  • MPICH_GATHERV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Gatherv_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCATTER_DEVICE_COLLECTIVE

• Aliases: - MVP_SCATTER_DEVICE_COLLECTIVE

  • MPICH_SCATTER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scatter will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ISCATTER_DEVICE_COLLECTIVE

• Aliases: - MVP_ISCATTER_DEVICE_COLLECTIVE

  • MPICH_ISCATTER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iscatter will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCATTER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_SCATTER_INIT_DEVICE_COLLECTIVE

  • MPICH_SCATTER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scatter_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCATTERV_DEVICE_COLLECTIVE

• Aliases: - MVP_SCATTERV_DEVICE_COLLECTIVE

  • MPICH_SCATTERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scatterv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ISCATTERV_DEVICE_COLLECTIVE

• Aliases: - MVP_ISCATTERV_DEVICE_COLLECTIVE

  • MPICH_ISCATTERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iscatterv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCATTERV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_SCATTERV_INIT_DEVICE_COLLECTIVE

  • MPICH_SCATTERV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scatterv_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLGATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLGATHER_DEVICE_COLLECTIVE

  • MPICH_ALLGATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allgather will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLGATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLGATHER_DEVICE_COLLECTIVE

  • MPICH_IALLGATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iallgather will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLGATHER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLGATHER_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLGATHER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allgather_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLGATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLGATHERV_DEVICE_COLLECTIVE

  • MPICH_ALLGATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allgatherv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLGATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLGATHERV_DEVICE_COLLECTIVE

  • MPICH_IALLGATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iallgatherv will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLGATHERV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLGATHERV_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLGATHERV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allgatherv_init will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALL_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALL_DEVICE_COLLECTIVE

  • MPICH_ALLTOALL_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoall will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLTOALL_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLTOALL_DEVICE_COLLECTIVE

  • MPICH_IALLTOALL_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ialltoall will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALL_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALL_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLTOALL_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoall_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALLV_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALLV_DEVICE_COLLECTIVE

  • MPICH_ALLTOALLV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoallv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLTOALLV_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLTOALLV_DEVICE_COLLECTIVE

  • MPICH_IALLTOALLV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ialltoallv will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALLV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALLV_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLTOALLV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoallv_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALLW_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALLW_DEVICE_COLLECTIVE

  • MPICH_ALLTOALLW_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoallw will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLTOALLW_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLTOALLW_DEVICE_COLLECTIVE

  • MPICH_IALLTOALLW_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ialltoallw will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLTOALLW_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLTOALLW_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLTOALLW_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Alltoallw_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_DEVICE_COLLECTIVE

  • MPICH_REDUCE_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IREDUCE_DEVICE_COLLECTIVE

• Aliases: - MVP_IREDUCE_DEVICE_COLLECTIVE

  • MPICH_IREDUCE_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ireduce will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_INIT_DEVICE_COLLECTIVE

  • MPICH_REDUCE_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLREDUCE_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLREDUCE_DEVICE_COLLECTIVE

  • MPICH_ALLREDUCE_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allreduce will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IALLREDUCE_DEVICE_COLLECTIVE

• Aliases: - MVP_IALLREDUCE_DEVICE_COLLECTIVE

  • MPICH_IALLREDUCE_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iallreduce will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ALLREDUCE_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_ALLREDUCE_INIT_DEVICE_COLLECTIVE

  • MPICH_ALLREDUCE_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Allreduce_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_SCATTER_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_SCATTER_DEVICE_COLLECTIVE

  • MPICH_REDUCE_SCATTER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce_scatter will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IREDUCE_SCATTER_DEVICE_COLLECTIVE

• Aliases: - MVP_IREDUCE_SCATTER_DEVICE_COLLECTIVE

  • MPICH_IREDUCE_SCATTER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ireduce_scatter will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_SCATTER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_SCATTER_INIT_DEVICE_COLLECTIVE

  • MPICH_REDUCE_SCATTER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce_scatter_init will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

  • MPICH_REDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce_scatter_block will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IREDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

• Aliases: - MVP_IREDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

  • MPICH_IREDUCE_SCATTER_BLOCK_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ireduce_scatter_block

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_REDUCE_SCATTER_BLOCK_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_REDUCE_SCATTER_BLOCK_INIT_DEVICE_COLLECTIVE

  • MPICH_REDUCE_SCATTER_BLOCK_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Reduce_scatter_block_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCAN_DEVICE_COLLECTIVE

• Aliases: - MVP_SCAN_DEVICE_COLLECTIVE

  • MPICH_SCAN_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scan will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_ISCAN_DEVICE_COLLECTIVE

• Aliases: - MVP_ISCAN_DEVICE_COLLECTIVE

  • MPICH_ISCAN_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iscan will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_SCAN_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_SCAN_INIT_DEVICE_COLLECTIVE

  • MPICH_SCAN_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Scan_init will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_EXSCAN_DEVICE_COLLECTIVE

• Aliases: - MVP_EXSCAN_DEVICE_COLLECTIVE

  • MPICH_EXSCAN_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Exscan will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_IEXSCAN_DEVICE_COLLECTIVE

• Aliases: - MVP_IEXSCAN_DEVICE_COLLECTIVE

  • MPICH_IEXSCAN_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Iexscan will allow the

  • device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_EXSCAN_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_EXSCAN_INIT_DEVICE_COLLECTIVE

  • MPICH_EXSCAN_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Exscan_init will allow

  • the device to override the MPIR-level collective algorithms. The

  • device might still call the MPIR-level algorithms manually. If set

  • to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_allgather will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_INEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

• Aliases: - MVP_INEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

  • MPICH_INEIGHBOR_ALLGATHER_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ineighbor_allgather will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLGATHER_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLGATHER_INIT_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLGATHER_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_allgather_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_allgatherv will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_INEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

• Aliases: - MVP_INEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

  • MPICH_INEIGHBOR_ALLGATHERV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ineighbor_allgatherv will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLGATHERV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLGATHERV_INIT_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLGATHERV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_allgatherv_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoall will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_INEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

• Aliases: - MVP_INEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

  • MPICH_INEIGHBOR_ALLTOALL_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ineighbor_alltoall will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALL_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALL_INIT_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALL_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoall_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoallv will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_INEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

• Aliases: - MVP_INEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

  • MPICH_INEIGHBOR_ALLTOALLV_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ineighbor_alltoallv will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALLV_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALLV_INIT_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALLV_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoallv_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoallw will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_INEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

• Aliases: - MVP_INEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

  • MPICH_INEIGHBOR_ALLTOALLW_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Ineighbor_alltoallw will

  • allow the device to override the MPIR-level collective algorithms.

  • The device might still call the MPIR-level algorithms manually. If

  • set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_NEIGHBOR_ALLTOALLW_INIT_DEVICE_COLLECTIVE

• Aliases: - MVP_NEIGHBOR_ALLTOALLW_INIT_DEVICE_COLLECTIVE

  • MPICH_NEIGHBOR_ALLTOALLW_INIT_DEVICE_COLLECTIVE

• Description: - This CVAR is only used when MPIR_CVAR_DEVICE_COLLECTIVES

  • is set to “percoll”. If set to true, MPI_Neighbor_alltoallw_init

  • will allow the device to override the MPIR-level collective

  • algorithms. The device might still call the MPIR-level algorithms

  • manually. If set to false, the device-override will be disabled.

• Default: 1

MPIR_CVAR_COLL_HYBRID_MEMORY

• Aliases: - MVP_COLL_HYBRID_MEMORY

  • MPICH_COLL_HYBRID_MEMORY

• Description: - This cvar indicates if the memory used in the collective

  • operations are the same type. It set to true, it means in a

  • collective operation, some buffers could be on the CPU and some

  • buffers could be on the GPU. If set to false, it means all the data

  • in a collective operation are on the same type of memory.

• Default: 1

MPIR_CVAR_GATHER_VSMALL_MSG_SIZE

• Aliases: - MVP_GATHER_VSMALL_MSG_SIZE

  • MPICH_GATHER_VSMALL_MSG_SIZE

• Description: - use a temporary buffer for intracommunicator MPI_Gather if

  • the send buffer size is < this value (in bytes) (See also:

  • MPIR_CVAR_GATHER_INTER_SHORT_MSG_SIZE)

• Default: 1024

MPIR_CVAR_IALLTOALL_BRUCKS_KVAL

• Aliases: - MVP_IALLTOALL_BRUCKS_KVAL

  • MPICH_IALLTOALL_BRUCKS_KVAL

• Description: - radix (k) value for generic transport brucks based

  • ialltoall

• Default: 2

MPIR_CVAR_IALLTOALL_BRUCKS_BUFFER_PER_NBR

• Aliases: - MVP_IALLTOALL_BRUCKS_BUFFER_PER_NBR

  • MPICH_IALLTOALL_BRUCKS_BUFFER_PER_NBR

• Description: - If set to true, the tsp based brucks algorithm will

  • allocate dedicated send and receive buffers for every neighbor in

  • the brucks algorithm. Otherwise, it would reuse a single buffer for

  • sending and receiving data to/from neighbors

• Default: 0

MPIR_CVAR_IALLTOALL_SCATTERED_OUTSTANDING_TASKS

• Aliases: - MVP_IALLTOALL_SCATTERED_OUTSTANDING_TASKS

  • MPICH_IALLTOALL_SCATTERED_OUTSTANDING_TASKS

• Description: - Maximum number of outstanding sends and recvs posted at a

  • time

• Default: 64

MPIR_CVAR_IALLTOALL_SCATTERED_BATCH_SIZE

• Aliases: - MVP_IALLTOALL_SCATTERED_BATCH_SIZE

  • MPICH_IALLTOALL_SCATTERED_BATCH_SIZE

• Description: - Number of send/receive tasks that scattered algorithm

  • waits for completion before posting another batch of send/receives

  • of that size

• Default: 4

MPIR_CVAR_BCAST_INTER_KNOMIAL_FACTOR

• Aliases: - MVP_BCAST_INTER_KNOMIAL_FACTOR

  • MPICH_BCAST_INTER_KNOMIAL_FACTOR

• Description: - This defines the degree of the knomial operation during

  • the inter-node knomial broadcast phase.

• Default: 4

MPIR_CVAR_BCAST_INTRA_KNOMIAL_FACTOR

• Aliases: - MVP_BCAST_INTRA_KNOMIAL_FACTOR

  • MPICH_BCAST_INTRA_KNOMIAL_FACTOR

• Description: - This defines the degree of the knomial operation during

  • the intra-node knomial broadcast phase.

• Default: 4

MPIR_CVAR_BCAST_SEGMENT_SIZE

• Aliases: - MVP_BCAST_SEGMENT_SIZE

  • MPICH_BCAST_SEGMENT_SIZE

• Description: - Size of the segments used for PIPELINED bcast

• Default: 8192

MPIR_CVAR_REDUCE_INTER_KNOMIAL_FACTOR

• Aliases: - MVP_REDUCE_INTER_KNOMIAL_FACTOR

  • MPICH_REDUCE_INTER_KNOMIAL_FACTOR

• Description: - This defines the degree of the knomial operation during

  • the inter-node knomial reduce phase.

• Default: 4

MPIR_CVAR_REDUCE_INTRA_KNOMIAL_FACTOR

• Aliases: - MVP_REDUCE_INTRA_KNOMIAL_FACTOR

  • MPICH_REDUCE_INTRA_KNOMIAL_FACTOR

• Description: - This defines the degree of the knomial operation during

  • the intra-node knomial reduce phase.

• Default: 4

MPIR_CVAR_DEVICE_COLLECTIVES

• Aliases: - MVP_DEVICE_COLLECTIVES

  • MPICH_DEVICE_COLLECTIVES

• Description: - Variable to select whether the device can override the

  • MPIR-level collective algorithms.

  • all - Always prefer the device collectives

  • none - Never pick the device collectives

  • percoll - Use the per-collective CVARs to decide

• Default: MPIR_CVAR_DEVICE_COLLECTIVES_percoll

MPIR_CVAR_COLLECTIVE_FALLBACK

• Aliases: - MVP_COLLECTIVE_FALLBACK

  • MPICH_COLLECTIVE_FALLBACK

• Description: - Variable to control what the MPI library should do if the

  • user-specified collective algorithm does not work for the

  • arguments passed in by the user.

  • error - throw an error

  • print - print an error message and fallback to the internally

  • selected algorithm

  • silent - silently fallback to the internally selected algorithm

• Default: MPIR_CVAR_COLLECTIVE_FALLBACK_silent

MPIR_CVAR_COLL_SELECTION_TUNING_JSON_FILE

• Aliases: - MVP_COLL_SELECTION_TUNING_JSON_FILE

  • MPICH_COLL_SELECTION_TUNING_JSON_FILE

• Description: - Defines the location of tuning file.

• Default: “”

MPIR_CVAR_HIERARCHY_DUMP

• Aliases: - MVP_HIERARCHY_DUMP

  • MPICH_HIERARCHY_DUMP

• Description: - If set to true, each rank will dump the hierarchy data

  • structure to a file named “hierarchy[rank]” in the current folder.

  • If set to false, the hierarchy data structure will not be dumped.

• Default: 0

MPIR_CVAR_COORDINATES_FILE

• Aliases: - MVP_COORDINATES_FILE

  • MPICH_COORDINATES_FILE

• Description: - Defines the location of the input coordinates file.

• Default: “”

MPIR_CVAR_COLL_TREE_DUMP

• Aliases: - MVP_COLL_TREE_DUMP

  • MPICH_COLL_TREE_DUMP

• Description: - If set to true, each rank will dump the tree to a file

  • named “colltree[rank].json” in the current folder. If set to false,

  • the tree will not be dumped.

• Default: 0

MPIR_CVAR_COORDINATES_DUMP

• Aliases: - MVP_COORDINATES_DUMP

  • MPICH_COORDINATES_DUMP

• Description: - If set to true, rank 0 will dump the network coordinates

  • to a file named “coords” in the current folder. If set to false,

  • the network coordinates will not be dumped.

• Default: 0

MPIR_CVAR_PROGRESS_MAX_COLLS

• Aliases: - MVP_PROGRESS_MAX_COLLS

  • MPICH_PROGRESS_MAX_COLLS

• Description: - Maximum number of collective operations at a time that the

  • progress engine should make progress on

• Default: 0

MPIR_CVAR_COMM_SPLIT_USE_QSORT

• Aliases: - MVP_COMM_SPLIT_USE_QSORT

  • MPICH_COMM_SPLIT_USE_QSORT

• Description: - Use qsort(3) in the implementation of MPI_Comm_split

  • instead of bubble sort.

• Default: 1

MPIR_CVAR_CTXID_EAGER_SIZE

• Aliases: - MVP_CTXID_EAGER_SIZE

  • MPICH_CTXID_EAGER_SIZE

• Description: - The MPIR_CVAR_CTXID_EAGER_SIZE environment variable allows

  • you to specify how many words in the context ID mask will be set

  • aside for the eager allocation protocol. If the application is

  • running out of context IDs, reducing this value may help.

• Default: 2

MPIR_CVAR_DATALOOP_FAST_SEEK

• Aliases: - MVP_DATALOOP_FAST_SEEK

  • MPICH_DATALOOP_FAST_SEEK

• Description: - use a datatype-specialized algorithm to shortcut seeking

  • to the correct location in a noncontiguous buffer

• Default: 1

MPIR_CVAR_YAKSA_COMPLEX_SUPPORT

• Aliases: - MVP_YAKSA_COMPLEX_SUPPORT

  • MPICH_YAKSA_COMPLEX_SUPPORT

• Description: - This CVAR indicates that complex type reduction is not

  • supported in yaksa.

• Default: 0

MPIR_CVAR_GPU_DOUBLE_SUPPORT

• Aliases: - MVP_GPU_DOUBLE_SUPPORT

  • MPICH_GPU_DOUBLE_SUPPORT

• Description: - This CVAR indicates that double type is not supported on

  • the GPU.

• Default: 0

MPIR_CVAR_GPU_LONG_DOUBLE_SUPPORT

• Aliases: - MVP_GPU_LONG_DOUBLE_SUPPORT

  • MPICH_GPU_LONG_DOUBLE_SUPPORT

• Description: - This CVAR indicates that double type is not supported on

  • the GPU.

• Default: 0

MPIR_CVAR_ENABLE_YAKSA_REDUCTION

• Aliases: - MVP_ENABLE_YAKSA_REDUCTION

  • MPICH_ENABLE_YAKSA_REDUCTION

• Description: - This cvar enables yaksa based reduction for local reduce.

• Default: 1

MPIR_CVAR_YAKSA_REDUCTION_THRESHOLD

• Aliases: - MVP_YAKSA_REDUCTION_THRESHOLD

  • MPICH_YAKSA_REDUCTION_THRESHOLD

• Description: - This cvar disables yaksa based reduction for messages

  • above the threshold. The default is no limit.

• Default: -1

MPIR_CVAR_PROCTABLE_SIZE

• Aliases: - MVP_PROCTABLE_SIZE

  • MPICH_PROCTABLE_SIZE

• Description: - Size of the “MPIR” debugger interface proctable (process

  • table).

• Default: 64

MPIR_CVAR_PROCTABLE_PRINT

• Aliases: - MVP_PROCTABLE_PRINT

  • MPICH_PROCTABLE_PRINT

• Description: - If true, dump the proctable entries at

  • MPII_Wait_for_debugger-time.

• Default: 0

MPIR_CVAR_PRINT_ERROR_STACK

• Aliases: - MVP_PRINT_ERROR_STACK

  • MPICH_PRINT_ERROR_STACK

• Description: - If true, print an error stack trace at error handling

  • time.

• Default: 1

MPIR_CVAR_CHOP_ERROR_STACK

• Aliases: - MVP_CHOP_ERROR_STACK

  • MPICH_CHOP_ERROR_STACK

• Description: - If >0, truncate error stack output lines this many

  • characters wide. If 0, do not truncate, and if <0 use a sensible

  • default.

• Default: 0

MPIR_CVAR_ASYNC_PROGRESS

• Aliases: - MVP_ASYNC_PROGRESS

  • MPICH_ASYNC_PROGRESS

• Description: - If set to true, MPICH will initiate an additional thread

  • to make asynchronous progress on all communication operations

  • including point-to-point, collective, one-sided operations and I/O.

  • Setting this variable will automatically increase the

  • thread-safety level to MPI_THREAD_MULTIPLE. While this improves

  • the progress semantics, it might cause a small amount of

  • performance overhead for regular MPI operations. The user is

  • encouraged to leave one or more hardware threads vacant in order to

  • prevent contention between the application threads and the progress

  • thread(s). The impact of oversubscription is highly system

  • dependent but may be substantial in some cases, hence this

  • recommendation.

• Default: 0

MPIR_CVAR_PROGRESS_THREAD_AFFINITY

• Aliases: - MVP_PROGRESS_THREAD_AFFINITY

  • MPICH_PROGRESS_THREAD_AFFINITY

• Description: - Specifies affinity for all progress threads of local

  • processes. Can be set to auto or comma-separated list of logical

  • processors. When set to auto - MPICH will automatically select

  • logical CPU cores to decide affinity of the progress threads. When

  • set to comma-separated list of logical processors - In case of N

  • progress threads per process, the first N logical processors from

  • list will be assigned to threads of first local process, the next N

  • logical processors from list - to second local process and so on.

  • For example, thread affinity is “0,1,2,3”, 2 progress threads per

  • process and 2 processes per node. Progress threads of first local

  • process will be pinned on logical processors “0,1”, progress

  • threads of second local process - on “2,3”. Cannot work together

  • with MPIR_CVAR_NUM_CLIQUES or MPIR_CVAR_ODD_EVEN_CLIQUES.

• Default: “”

MPIR_CVAR_SUPPRESS_ABORT_MESSAGE

• Aliases: - MVP_SUPPRESS_ABORT_MESSAGE

  • MPICH_SUPPRESS_ABORT_MESSAGE

• Description: - Disable printing of abort error message.

• Default: 0

MPIR_CVAR_COREDUMP_ON_ABORT

• Aliases: - MVP_COREDUMP_ON_ABORT

  • MPICH_COREDUMP_ON_ABORT

• Description: - Call libc abort() to generate a corefile

• Default: 0

MPIR_CVAR_ERROR_CHECKING

• Aliases: - MVP_ERROR_CHECKING

  • MPICH_ERROR_CHECKING

• Description: - If true, perform checks for errors, typically to verify

  • valid inputs to MPI routines. Only effective when MPICH is

  • configured with –enable-error-checking=runtime .

• Default: 1

MPIR_CVAR_MEMDUMP

• Aliases: - MVP_MEMDUMP

  • MPICH_MEMDUMP

• Description: - If true, list any memory that was allocated by MPICH and

  • that remains allocated when MPI_Finalize completes.

• Default: 1

MPIR_CVAR_DEBUG_SUMMARY

• Aliases: - MVP_DEBUG_SUMMARY

  • MPICH_DEBUG_SUMMARY

  • MPIR_CVAR_MEM_CATEGORY_INFORMATION

  • MPIR_CVAR_CH4_OFI_CAPABILITY_SETS_DEBUG

  • MPIR_CVAR_CH4_UCX_CAPABILITY_DEBUG

  • MVP_MEM_CATEGORY_INFORMATION

  • MVP_CH4_OFI_CAPABILITY_SETS_DEBUG

  • MVP_CH4_UCX_CAPABILITY_DEBUG

  • MPICH_MEM_CATEGORY_INFORMATION

  • MPICH_CH4_OFI_CAPABILITY_SETS_DEBUG

  • MPICH_CH4_UCX_CAPABILITY_DEBUG

• Description: - 1: Print internal summary of various debug information,

  • such as memory allocation by category. Each layer may print their

  • own summary information. For example, ch4-ofi may print its

  • provider capability settings. 2: Also print the preferred NIC for

  • each rank

• Default: 0

MPIR_CVAR_DEFAULT_THREAD_LEVEL

• Aliases: - MVP_DEFAULT_THREAD_LEVEL

  • MPICH_DEFAULT_THREAD_LEVEL

• Description: - Sets the default thread level to use when using MPI_INIT.

  • This variable is case-insensitive.

• Default: “MPI_THREAD_SINGLE”

MPIR_CVAR_DEBUG_HOLD

• Aliases: - MVP_DEBUG_HOLD

  • MPICH_DEBUG_HOLD

• Description: - If true, causes processes to wait in MPI_Init and

  • MPI_Initthread for a debugger to be attached. Once the debugger

  • has attached, the variable ‘hold’ should be set to 0 in order to

  • allow the process to continue (e.g., in gdb, “set hold=0”).

• Default: 0

MPIR_CVAR_GPU_USE_IMMEDIATE_COMMAND_LIST

• Aliases: - MVP_GPU_USE_IMMEDIATE_COMMAND_LIST

  • MPICH_GPU_USE_IMMEDIATE_COMMAND_LIST

• Description: - If true, mpl/ze will use immediate command list for

  • copying

• Default: 0

MPIR_CVAR_GPU_ROUND_ROBIN_COMMAND_QUEUES

• Aliases: - MVP_GPU_ROUND_ROBIN_COMMAND_QUEUES

  • MPICH_GPU_ROUND_ROBIN_COMMAND_QUEUES

• Description: - If true, mpl/ze will use command queues in a round-robin

  • fashion. If false, only command queues of index 0 will be used.

• Default: 0

MPIR_CVAR_NO_COLLECTIVE_FINALIZE

• Aliases: - MVP_NO_COLLECTIVE_FINALIZE

  • MPICH_NO_COLLECTIVE_FINALIZE

• Description: - If true, prevent MPI_Finalize to invoke collective

  • behavior such as barrier or communicating to other processes.

  • Consequently, it may result in leaking memory or losing messages

  • due to pre-mature exiting. The default is false, which may invoke

  • collective behaviors at finalize.

• Default: 0

MPIR_CVAR_FINALIZE_WAIT

• Aliases: - MVP_FINALIZE_WAIT

  • MPICH_FINALIZE_WAIT

• Description: - If true, poll progress at MPI_Finalize until reference

  • count on MPI_COMM_WORLD and MPI_COMM_SELF reaches zero. This may be

  • necessary to prevent remote processes hanging if it has pending

  • communication protocols, e.g. a rendezvous send.

• Default: 0

MPIR_CVAR_INIT_SKIP_PMI_BARRIER

• Aliases: - MVP_INIT_SKIP_PMI_BARRIER

  • MPICH_INIT_SKIP_PMI_BARRIER

• Description: - Skip MPIR_pmi_barrier() in MPI_Init

• Default: 1

MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE

• Aliases: - MVP_GPU_FAST_COPY_MAX_SIZE

  • MPICH_GPU_FAST_COPY_MAX_SIZE

• Description: - If a send message size is less than or equal to

  • MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE (in bytes), then enable GPU-based

  • fast memcpy. The environment variable is valid only when then GPU

  • IPC shmmod is enabled.

• Default: 4096

MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE_H2D

• Aliases: - MVP_GPU_FAST_COPY_MAX_SIZE_H2D

  • MPICH_GPU_FAST_COPY_MAX_SIZE_H2D

• Description: - If a receive message size is less than or equal to

  • MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE_H2D (in bytes), then enable

  • GPU-based fast memcpy.

• Default: 1048576

MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE_D2H

• Aliases: - MVP_GPU_FAST_COPY_MAX_SIZE_D2H

  • MPICH_GPU_FAST_COPY_MAX_SIZE_D2H

• Description: - If a send message size is less than or equal to

  • MPIR_CVAR_GPU_FAST_COPY_MAX_SIZE_D2H (in bytes), then enable

  • GPU-based fast memcpy.

• Default: 32768

MPIR_CVAR_REQUEST_ERR_FATAL

• Aliases: - MVP_REQUEST_ERR_FATAL

  • MPICH_REQUEST_ERR_FATAL

• Description: - By default, MPI_Waitall, MPI_Testall, MPI_Waitsome, and

  • MPI_Testsome return MPI_ERR_IN_STATUS when one of the request

  • fails. If MPIR_CVAR_REQUEST_ERR_FATAL is set to true, these

  • routines will return the error code of the request immediately. The

  • default MPI_ERRS_ARE_FATAL error handler will dump a error stack in

  • this case, which maybe more convenient for debugging. This cvar

  • will also make nonblocking shched return error right away as it

  • issues operations.

• Default: 0

MPIR_CVAR_REQUEST_POLL_FREQ

• Aliases: - MVP_REQUEST_POLL_FREQ

  • MPICH_REQUEST_POLL_FREQ

• Description: - How frequent to poll during MPI_{Waitany,Waitsome} in

  • terms of number of processed requests before polling.

• Default: 8

MPIR_CVAR_REQUEST_BATCH_SIZE

• Aliases: - MVP_REQUEST_BATCH_SIZE

  • MPICH_REQUEST_BATCH_SIZE

• Description: - The number of requests to make completion as a batch in

  • MPI_Waitall and MPI_Testall implementation. A large number is

  • likely to cause more cache misses.

• Default: 64

MPIR_CVAR_DEBUG_PROGRESS_TIMEOUT

• Aliases: - MVP_DEBUG_PROGRESS_TIMEOUT

  • MPICH_DEBUG_PROGRESS_TIMEOUT

• Description: - Sets the timeout in seconds to dump outstanding requests

  • when progress wait is not making progress for some time.

• Default: 0

MPIR_CVAR_DIMS_VERBOSE

• Aliases: - MVP_DIMS_VERBOSE

  • MPICH_DIMS_VERBOSE

• Description: - If true, enable verbose output about the actions of the

  • implementation of MPI_Dims_create.

• Default: 0

MPIR_CVAR_QMPI_TOOL_LIST

• Aliases: - MVP_QMPI_TOOL_LIST

  • MPICH_QMPI_TOOL_LIST

• Description: - Set the number and order of QMPI tools to be loaded by the

  • MPI library when it is initialized.

• Default: NULL

MPIR_CVAR_NAMESERV_FILE_PUBDIR

• Aliases: - MVP_NAMESERV_FILE_PUBDIR

  • MPICH_NAMESERV_FILE_PUBDIR

  • MPIR_CVAR_NAMEPUB_DIR

  • MVP_NAMEPUB_DIR

  • MPICH_NAMEPUB_DIR

• Description: - Sets the directory to use for MPI service publishing in

  • the file nameserv implementation. Allows the user to override

  • where the publish and lookup information is placed for

  • connect/accept based applications.

• Default: NULL

MPIR_CVAR_ABORT_ON_LEAKED_HANDLES

• Aliases: - MVP_ABORT_ON_LEAKED_HANDLES

  • MPICH_ABORT_ON_LEAKED_HANDLES

• Description: - If true, MPI will call MPI_Abort at MPI_Finalize if any

  • MPI object handles have been leaked. For example, if MPI_Comm_dup

  • is called without calling a corresponding MPI_Comm_free. For

  • uninteresting reasons, enabling this option may prevent all known

  • object leaks from being reported. MPICH must have been configure

  • with “–enable-g=handlealloc” or better in order for this

  • functionality to work.

• Default: 0

MPIR_CVAR_NETLOC_NODE_FILE

• Aliases: - MVP_NETLOC_NODE_FILE

  • MPICH_NETLOC_NODE_FILE

• Description: - Subnet json file

• Default: “auto”

MPIR_CVAR_NOLOCAL

• Aliases: - MVP_NOLOCAL

  • MPICH_NOLOCAL

  • MPIR_CVAR_NO_LOCAL

  • MVP_NO_LOCAL

  • MPICH_NO_LOCAL

• Description: - If true, force all processes to operate as though all

  • processes are located on another node. For example, this disables

  • shared memory communication hierarchical collectives.

• Default: 0

MPIR_CVAR_ODD_EVEN_CLIQUES

• Aliases: - MVP_ODD_EVEN_CLIQUES

  • MPICH_ODD_EVEN_CLIQUES

  • MPIR_CVAR_EVEN_ODD_CLIQUES

  • MVP_EVEN_ODD_CLIQUES

  • MPICH_EVEN_ODD_CLIQUES

• Description: - If true, odd procs on a node are seen as local to each

  • other, and even procs on a node are seen as local to each other.

  • Used for debugging on a single machine. Deprecated in favor of

  • MPIR_CVAR_NUM_CLIQUES.

• Default: 0

MPIR_CVAR_NUM_CLIQUES

• Aliases: - MVP_NUM_CLIQUES

  • MPICH_NUM_CLIQUES

• Description: - Specify the number of cliques that should be used to

  • partition procs on a local node. Procs with the same clique number

  • are seen as local to each other. Used for debugging on a single

  • machine.

• Default: 1

MPIR_CVAR_CLIQUES_BY_BLOCK

• Aliases: - MVP_CLIQUES_BY_BLOCK

  • MPICH_CLIQUES_BY_BLOCK

• Description: - Specify to divide processes into cliques by uniform

  • blocks. The default is to divide in round-robin fashion. Used for

  • debugging on a single machine.

• Default: 0

MPIR_CVAR_PMI_VERSION

• Aliases: - MVP_PMI_VERSION

  • MPICH_PMI_VERSION

• Description: - Variable to select runtime PMI version.

  • 1 - - PMI (default)

  • 2 - - PMI2

  • x - - PMIx

• Default: MPIR_CVAR_PMI_VERSION_1

MPIR_CVAR_COLL_ALIAS_CHECK

• Aliases: - MVP_COLL_ALIAS_CHECK

  • MPICH_COLL_ALIAS_CHECK

• Description: - Enable checking of aliasing in collective operations

• Default: 1

MPIR_CVAR_ENABLE_GPU

• Aliases: - MVP_ENABLE_GPU

  • MPICH_ENABLE_GPU

• Description: - Control MPICH GPU support. If set to 0, all GPU support is

  • disabled and we do not query the buffer type internally because we

  • assume no GPU buffer is use.

• Default: 1

MPIR_CVAR_GPU_HAS_WAIT_KERNEL

• Aliases: - MVP_GPU_HAS_WAIT_KERNEL

  • MPICH_GPU_HAS_WAIT_KERNEL

• Description: - If set to 1, avoid allocate allocating GPU registered host

  • buffers for temporary buffers. When stream workq and GPU wait

  • kernels are in use, access APIs for GPU registered memory may cause

  • deadlock.

• Default: 0

MPIR_CVAR_ENABLE_GPU_REGISTER

• Aliases: - MVP_ENABLE_GPU_REGISTER

  • MPICH_ENABLE_GPU_REGISTER

• Description: - Control whether to actually register buffers with the GPU

  • runtime in MPIR_gpu_register_host. This could lower the latency of

  • certain GPU communication at the cost of some amount of GPU memory

  • consumed by the MPI library. By default, registration is enabled.

• Default: 1

MPIR_CVAR_LMEM_POOL_SIZE

• Aliases: - MVP_LMEM_POOL_SIZE

  • MPICH_LMEM_POOL_SIZE

• Description: - Sets the amount of space allocated at init time to be used

  • by internal functions for local temp buffers.

• Default: 32 * 1024 * 1024

MPIR_CVAR_POLLS_BEFORE_YIELD

• Aliases: - MVP_POLLS_BEFORE_YIELD

  • MPICH_POLLS_BEFORE_YIELD

• Description: - When MPICH is in a busy waiting loop, it will periodically

  • call a function to yield the processor. This cvar sets the number

  • of loops before the yield function is called. A value of 0

  • disables yielding.

• Default: 1000

MPIR_CVAR_CH3_INTERFACE_HOSTNAME

• Aliases: - MVP_CH3_INTERFACE_HOSTNAME

  • MPICH_CH3_INTERFACE_HOSTNAME

  • MPIR_CVAR_INTERFACE_HOSTNAME

  • MVP_INTERFACE_HOSTNAME

  • MPICH_INTERFACE_HOSTNAME

• Description: - If non-NULL, this cvar specifies the IP address that other

  • processes should use when connecting to this process. This cvar is

  • mutually exclusive with the MPIR_CVAR_CH3_NETWORK_IFACE cvar and it

  • is an error to set them both.

• Default: NULL

MPIR_CVAR_CH3_PORT_RANGE

• Aliases: - MVP_CH3_PORT_RANGE

  • MPICH_CH3_PORT_RANGE

  • MPIR_CVAR_PORTRANGE

  • MPIR_CVAR_PORT_RANGE

  • MVP_PORTRANGE

  • MVP_PORT_RANGE

  • MPICH_PORTRANGE

  • MPICH_PORT_RANGE

• Description: - The MPIR_CVAR_CH3_PORT_RANGE environment variable allows

  • you to specify the range of TCP ports to be used by the process

  • manager and the MPICH library. The format of this variable is

  • <low>:<high>. To specify any available port, use 0:0.

• Default: {0,0}

MPIR_CVAR_NEMESIS_TCP_NETWORK_IFACE

• Aliases: - MVP_NEMESIS_TCP_NETWORK_IFACE

  • MPICH_NEMESIS_TCP_NETWORK_IFACE

  • MPIR_CVAR_NETWORK_IFACE

  • MVP_NETWORK_IFACE

  • MPICH_NETWORK_IFACE

• Description: - If non-NULL, this cvar specifies which pseudo-ethernet

  • interface the tcp netmod should use (e.g., “eth1”, “ib0”). Note,

  • this is a Linux-specific cvar. This cvar is mutually exclusive with

  • the MPIR_CVAR_CH3_INTERFACE_HOSTNAME cvar and it is an error to set

  • them both.

• Default: NULL

MPIR_CVAR_NEMESIS_TCP_HOST_LOOKUP_RETRIES

• Aliases: - MVP_NEMESIS_TCP_HOST_LOOKUP_RETRIES

  • MPICH_NEMESIS_TCP_HOST_LOOKUP_RETRIES

• Description: - This cvar controls the number of times to retry the

  • gethostbyname() function before giving up.

• Default: 10

MPIR_CVAR_NEMESIS_ENABLE_CKPOINT

• Aliases: - MVP_NEMESIS_ENABLE_CKPOINT

  • MPICH_NEMESIS_ENABLE_CKPOINT

• Description: - If true, enables checkpointing support and returns an

  • error if checkpointing library cannot be initialized.

• Default: 0

MPIR_CVAR_NEMESIS_SHM_EAGER_MAX_SZ

• Aliases: - MVP_NEMESIS_SHM_EAGER_MAX_SZ

  • MPICH_NEMESIS_SHM_EAGER_MAX_SZ

• Description: - This cvar controls the message size at which Nemesis

  • switches from eager to rendezvous mode for shared memory. If this

  • cvar is set to -1, then Nemesis will choose an appropriate value.

• Default: -1

MPIR_CVAR_NEMESIS_SHM_READY_EAGER_MAX_SZ

• Aliases: - MVP_NEMESIS_SHM_READY_EAGER_MAX_SZ

  • MPICH_NEMESIS_SHM_READY_EAGER_MAX_SZ

• Description: - This cvar controls the message size at which Nemesis

  • switches from eager to rendezvous mode for ready-send messages. If

  • this cvar is set to -1, then ready messages will always be sent

  • eagerly. If this cvar is set to -2, then Nemesis will choose an

  • appropriate value.

• Default: -2

MPIR_CVAR_ENABLE_FT

• Aliases: - MVP_ENABLE_FT

  • MPICH_ENABLE_FT

• Description: - Enable fault tolerance functions

• Default: 0

MPIR_CVAR_NEMESIS_NETMOD

• Aliases: - MVP_NEMESIS_NETMOD

  • MPICH_NEMESIS_NETMOD

• Description: - If non-empty, this cvar specifies which network module

  • should be used for communication. This variable is

  • case-insensitive.

• Default: “”

MPIR_CVAR_CH3_ENABLE_HCOLL

• Aliases: - MVP_CH3_ENABLE_HCOLL

  • MPICH_CH3_ENABLE_HCOLL

• Description: - If true, enable HCOLL collectives.

• Default: 0

MPIR_CVAR_CH3_COMM_CONNECT_TIMEOUT

• Aliases: - MVP_CH3_COMM_CONNECT_TIMEOUT

  • MPICH_CH3_COMM_CONNECT_TIMEOUT

• Description: - The default time out period in seconds for a connection

  • attempt to the server communicator where the named port exists but

  • no pending accept. User can change the value for a specified

  • connection through its info argument.

• Default: 180

MPIR_CVAR_CH3_RMA_OP_PIGGYBACK_LOCK_DATA_SIZE

• Aliases: - MVP_CH3_RMA_OP_PIGGYBACK_LOCK_DATA_SIZE

  • MPICH_CH3_RMA_OP_PIGGYBACK_LOCK_DATA_SIZE

• Description: - Specify the threshold of data size of a RMA operation

  • which can be piggybacked with a LOCK message. It is always a

  • positive value and should not be smaller than

  • MPIDI_RMA_IMMED_BYTES. If user sets it as a small value, for middle

  • and large data size, we will lose performance because of always

  • waiting for round-trip of LOCK synchronization; if user sets it as

  • a large value, we need to consume more memory on target side to

  • buffer this lock request when lock is not satisfied.

• Default: 65536

MPIR_CVAR_CH3_RMA_ACTIVE_REQ_THRESHOLD

• Aliases: - MVP_CH3_RMA_ACTIVE_REQ_THRESHOLD

  • MPICH_CH3_RMA_ACTIVE_REQ_THRESHOLD

• Description: - Threshold of number of active requests to trigger blocking

  • waiting in operation routines. When the value is negative, we never

  • blockingly wait in operation routines. When the value is zero, we

  • always trigger blocking waiting in operation routines to wait until

  • no. of active requests becomes zero. When the value is positive, we

  • do blocking waiting in operation routines to wait until no. of

  • active requests being reduced to this value.

• Default: 65536

MPIR_CVAR_CH3_RMA_POKE_PROGRESS_REQ_THRESHOLD

• Aliases: - MVP_CH3_RMA_POKE_PROGRESS_REQ_THRESHOLD

  • MPICH_CH3_RMA_POKE_PROGRESS_REQ_THRESHOLD

• Description: - Threshold at which the RMA implementation attempts to

  • complete requests while completing RMA operations and while using

  • the lazy synchronization approach. Change this value if programs

  • fail because they run out of requests or other internal resources

• Default: 128

MPIR_CVAR_CH3_RMA_SCALABLE_FENCE_PROCESS_NUM

• Aliases: - MVP_CH3_RMA_SCALABLE_FENCE_PROCESS_NUM

  • MPICH_CH3_RMA_SCALABLE_FENCE_PROCESS_NUM

• Description: - Specify the threshold of switching the algorithm used in

  • FENCE from the basic algorithm to the scalable algorithm. The value

  • can be negative, zero or positive. When the number of processes is

  • larger than or equal to this value, FENCE will use a scalable

  • algorithm which do not use O(P) data structure; when the number of

  • processes is smaller than the value, FENCE will use a basic but

  • fast algorithm which requires an O(P) data structure.

• Default: 1024

MPIR_CVAR_CH3_RMA_DELAY_ISSUING_FOR_PIGGYBACKING

• Aliases: - MVP_CH3_RMA_DELAY_ISSUING_FOR_PIGGYBACKING

  • MPICH_CH3_RMA_DELAY_ISSUING_FOR_PIGGYBACKING

• Description: - Specify if delay issuing of RMA operations for

  • piggybacking LOCK/UNLOCK/FLUSH is enabled. It can be either 0 or 1.

  • When it is set to 1, the issuing of LOCK message is delayed until

  • origin process see the first RMA operation and piggyback LOCK with

  • that operation, and the origin process always keeps the current

  • last operation until the ending synchronization call in order to

  • piggyback UNLOCK/FLUSH with that operation. When it is set to 0, in

  • WIN_LOCK/UNLOCK case, the LOCK message is sent out as early as

  • possible, in WIN_LOCK_ALL/UNLOCK_ALL case, the origin process still

  • tries to piggyback LOCK message with the first operation; for

  • UNLOCK/FLUSH message, the origin process no longer keeps the

  • current last operation but only piggyback UNLOCK/FLUSH if there is

  • an operation available in the ending synchronization call.

• Default: 0

MPIR_CVAR_CH3_RMA_SLOTS_SIZE

• Aliases: - MVP_CH3_RMA_SLOTS_SIZE

  • MPICH_CH3_RMA_SLOTS_SIZE

• Description: - Number of RMA slots during window creation. Each slot

  • contains a linked list of target elements. The distribution of

  • ranks among slots follows a round-robin pattern. Requires a

  • positive value.

• Default: 262144

MPIR_CVAR_CH3_RMA_TARGET_LOCK_DATA_BYTES

• Aliases: - MVP_CH3_RMA_TARGET_LOCK_DATA_BYTES

  • MPICH_CH3_RMA_TARGET_LOCK_DATA_BYTES

• Description: - Size (in bytes) of available lock data this window can

  • provided. If current buffered lock data is more than this value,

  • the process will drop the upcoming operation data. Requires a

  • positive value.

• Default: 655360

MPIR_CVAR_CH3_EAGER_MAX_MSG_SIZE

• Aliases: - MVP_CH3_EAGER_MAX_MSG_SIZE

  • MPICH_CH3_EAGER_MAX_MSG_SIZE

• Description: - This cvar controls the message size at which CH3 switches

  • from eager to rendezvous mode.

• Default: 131072

MPIR_CVAR_CH3_PG_VERBOSE

• Aliases: - MVP_CH3_PG_VERBOSE

  • MPICH_CH3_PG_VERBOSE

• Description: - If set, print the PG state on finalize.

• Default: 0

MPIR_CVAR_CH3_RMA_OP_WIN_POOL_SIZE

• Aliases: - MVP_CH3_RMA_OP_WIN_POOL_SIZE

  • MPICH_CH3_RMA_OP_WIN_POOL_SIZE

• Description: - Size of the window-private RMA operations pool (in number

  • of operations) that stores information about RMA operations that

  • could not be issued immediately. Requires a positive value.

• Default: 256

MPIR_CVAR_CH3_RMA_OP_GLOBAL_POOL_SIZE

• Aliases: - MVP_CH3_RMA_OP_GLOBAL_POOL_SIZE

  • MPICH_CH3_RMA_OP_GLOBAL_POOL_SIZE

• Description: - Size of the Global RMA operations pool (in number of

  • operations) that stores information about RMA operations that could

  • not be issued immediately. Requires a positive value.

• Default: 16384

MPIR_CVAR_CH3_RMA_TARGET_WIN_POOL_SIZE

• Aliases: - MVP_CH3_RMA_TARGET_WIN_POOL_SIZE

  • MPICH_CH3_RMA_TARGET_WIN_POOL_SIZE

• Description: - Size of the window-private RMA target pool (in number of

  • targets) that stores information about RMA targets that could not

  • be issued immediately. Requires a positive value.

• Default: 256

MPIR_CVAR_CH3_RMA_TARGET_GLOBAL_POOL_SIZE

• Aliases: - MVP_CH3_RMA_TARGET_GLOBAL_POOL_SIZE

  • MPICH_CH3_RMA_TARGET_GLOBAL_POOL_SIZE

• Description: - Size of the Global RMA targets pool (in number of targets)

  • that stores information about RMA targets that could not be issued

  • immediately. Requires a positive value.

• Default: 16384

MPIR_CVAR_CH3_RMA_TARGET_LOCK_ENTRY_WIN_POOL_SIZE

• Aliases: - MVP_CH3_RMA_TARGET_LOCK_ENTRY_WIN_POOL_SIZE

  • MPICH_CH3_RMA_TARGET_LOCK_ENTRY_WIN_POOL_SIZE

• Description: - Size of the window-private RMA lock entries pool (in

  • number of lock entries) that stores information about RMA lock

  • requests that could not be satisfied immediately. Requires a

  • positive value.

• Default: 256

MPIR_CVAR_OFI_USE_PROVIDER

• Aliases: - MVP_OFI_USE_PROVIDER

  • MPICH_OFI_USE_PROVIDER

• Description: - This variable is no longer supported. Use FI_PROVIDER

  • instead to select libfabric providers.

• Default: NULL

MPIR_CVAR_SINGLE_HOST_ENABLED

• Aliases: - MVP_SINGLE_HOST_ENABLED

  • MPICH_SINGLE_HOST_ENABLED

• Description: - Set this variable to true to indicate that processes are

  • launched on a single host. The current implication is to avoid the

  • cxi provider to prevent the use of scarce hardware resources.

• Default: 1

MPIR_CVAR_CH4_OFI_AM_LONG_FORCE_PIPELINE

• Aliases: - MVP_CH4_OFI_AM_LONG_FORCE_PIPELINE

  • MPICH_CH4_OFI_AM_LONG_FORCE_PIPELINE

• Description: - For long message to be sent using pipeline rather than

  • default RDMA read.

• Default: 0

MPIR_CVAR_BCAST_OFI_INTRA_ALGORITHM

• Aliases: - MVP_BCAST_OFI_INTRA_ALGORITHM

  • MPICH_BCAST_OFI_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node bcast

  • mpir - - - - Fallback to MPIR collectives

  • trigger_tree_tagged - - Force triggered ops based Tagged Tree

  • trigger_tree_rma - - Force triggered ops based RMA Tree

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_OFI_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_BCAST_OFI_INTRA_ALGORITHM_auto

MPIR_CVAR_CH4_OFI_GPU_RECEIVE_ENGINE_TYPE

• Aliases: - MVP_CH4_OFI_GPU_RECEIVE_ENGINE_TYPE

  • MPICH_CH4_OFI_GPU_RECEIVE_ENGINE_TYPE

• Description: - Specifies GPU engine type for GPU pt2pt on the receiver

  • side.

  • compute - use a compute engine

  • copy_high_bandwidth - use a high-bandwidth copy engine

  • copy_low_latency - use a low-latency copy engine

  • yaksa - use Yaksa

• Default: MPIR_CVAR_CH4_OFI_GPU_RECEIVE_ENGINE_TYPE_copy_low_latency

MPIR_CVAR_OFI_SKIP_IPV6

• Aliases: - MVP_OFI_SKIP_IPV6

  • MPICH_OFI_SKIP_IPV6

• Description: - Skip IPv6 providers.

• Default: 0

MPIR_CVAR_CH4_OFI_ENABLE_DATA

• Aliases: - MVP_CH4_OFI_ENABLE_DATA

  • MPICH_CH4_OFI_ENABLE_DATA

• Description: - Enable immediate data fields in OFI to transmit source

  • rank outside of the match bits

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_AV_TABLE

• Aliases: - MVP_CH4_OFI_ENABLE_AV_TABLE

  • MPICH_CH4_OFI_ENABLE_AV_TABLE

• Description: - If true, the OFI addressing information will be stored

  • with an FI_AV_TABLE. If false, an FI_AV_MAP will be used.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_SCALABLE_ENDPOINTS

• Aliases: - MVP_CH4_OFI_ENABLE_SCALABLE_ENDPOINTS

  • MPICH_CH4_OFI_ENABLE_SCALABLE_ENDPOINTS

• Description: - If true, use OFI scalable endpoints.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_SHARED_CONTEXTS

• Aliases: - MVP_CH4_OFI_ENABLE_SHARED_CONTEXTS

  • MPICH_CH4_OFI_ENABLE_SHARED_CONTEXTS

• Description: - If set to false (zero), MPICH does not use OFI shared

  • contexts. If set to -1, it is determined by the OFI capability sets

  • based on the provider. Otherwise, MPICH tries to use OFI shared

  • contexts. If they are unavailable, it’ll fall back to the mode

  • without shared contexts.

• Default: 0

MPIR_CVAR_CH4_OFI_ENABLE_MR_VIRT_ADDRESS

• Aliases: - MVP_CH4_OFI_ENABLE_MR_VIRT_ADDRESS

  • MPICH_CH4_OFI_ENABLE_MR_VIRT_ADDRESS

• Description: - If true, enable virtual addressing for OFI memory regions.

  • This variable is only meaningful for OFI versions 1.5+. It is

  • equivalent to using FI_MR_BASIC in versions of OFI older than 1.5.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_MR_ALLOCATED

• Aliases: - MVP_CH4_OFI_ENABLE_MR_ALLOCATED

  • MPICH_CH4_OFI_ENABLE_MR_ALLOCATED

• Description: - If true, require all OFI memory regions must be backed by

  • physical memory pages at the time the registration call is made.

  • This variable is only meaningful for OFI versions 1.5+. It is

  • equivalent to using FI_MR_BASIC in versions of OFI older than 1.5.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_MR_REGISTER_NULL

• Aliases: - MVP_CH4_OFI_ENABLE_MR_REGISTER_NULL

  • MPICH_CH4_OFI_ENABLE_MR_REGISTER_NULL

• Description: - If true, memory registration call supports registering

  • with NULL addresses.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_MR_PROV_KEY

• Aliases: - MVP_CH4_OFI_ENABLE_MR_PROV_KEY

  • MPICH_CH4_OFI_ENABLE_MR_PROV_KEY

• Description: - If true, enable provider supplied key for OFI memory

  • regions. This variable is only meaningful for OFI versions 1.5+. It

  • is equivalent to using FI_MR_BASIC in versions of OFI older than

  • 1.5.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_TAGGED

• Aliases: - MVP_CH4_OFI_ENABLE_TAGGED

  • MPICH_CH4_OFI_ENABLE_TAGGED

• Description: - If true, use tagged message transmission functions in OFI.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_AM

• Aliases: - MVP_CH4_OFI_ENABLE_AM

  • MPICH_CH4_OFI_ENABLE_AM

• Description: - If true, enable OFI active message support.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_RMA

• Aliases: - MVP_CH4_OFI_ENABLE_RMA

  • MPICH_CH4_OFI_ENABLE_RMA

• Description: - If true, enable OFI RMA support for MPI RMA operations.

  • OFI support for basic RMA is always required to implement large

  • messgage transfers in the active message code path.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_ATOMICS

• Aliases: - MVP_CH4_OFI_ENABLE_ATOMICS

  • MPICH_CH4_OFI_ENABLE_ATOMICS

• Description: - If true, enable OFI Atomics support.

• Default: -1

MPIR_CVAR_CH4_OFI_FETCH_ATOMIC_IOVECS

• Aliases: - MVP_CH4_OFI_FETCH_ATOMIC_IOVECS

  • MPICH_CH4_OFI_FETCH_ATOMIC_IOVECS

• Description: - Specifies the maximum number of iovecs that can be used by

  • the OFI provider for fetch_atomic operations. The default value is

  • -1, indicating that no value is set.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_DATA_AUTO_PROGRESS

• Aliases: - MVP_CH4_OFI_ENABLE_DATA_AUTO_PROGRESS

  • MPICH_CH4_OFI_ENABLE_DATA_AUTO_PROGRESS

• Description: - If true, enable MPI data auto progress.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_CONTROL_AUTO_PROGRESS

• Aliases: - MVP_CH4_OFI_ENABLE_CONTROL_AUTO_PROGRESS

  • MPICH_CH4_OFI_ENABLE_CONTROL_AUTO_PROGRESS

• Description: - If true, enable MPI control auto progress.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_PT2PT_NOPACK

• Aliases: - MVP_CH4_OFI_ENABLE_PT2PT_NOPACK

  • MPICH_CH4_OFI_ENABLE_PT2PT_NOPACK

• Description: - If true, enable iovec for pt2pt.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_HMEM

• Aliases: - MVP_CH4_OFI_ENABLE_HMEM

  • MPICH_CH4_OFI_ENABLE_HMEM

• Description: - If true, uses GPU direct RDMA support in the provider.

• Default: 0

MPIR_CVAR_CH4_OFI_ENABLE_MR_HMEM

• Aliases: - MVP_CH4_OFI_ENABLE_MR_HMEM

  • MPICH_CH4_OFI_ENABLE_MR_HMEM

• Description: - If true, need to register the buffer to use GPU direct

  • RDMA.

• Default: -1

MPIR_CVAR_CH4_OFI_GPU_RDMA_THRESHOLD

• Aliases: - MVP_CH4_OFI_GPU_RDMA_THRESHOLD

  • MPICH_CH4_OFI_GPU_RDMA_THRESHOLD

• Description: - The threshold to start using GPU direct RDMA.

• Default: 0

MPIR_CVAR_CH4_OFI_CONTEXT_ID_BITS

• Aliases: - MVP_CH4_OFI_CONTEXT_ID_BITS

  • MPICH_CH4_OFI_CONTEXT_ID_BITS

• Description: - Specifies the number of bits that will be used for

  • matching the context ID. The default value is -1, indicating that

  • no value is set and that the default will be defined in the

  • ofi_types.h file.

• Default: -1

MPIR_CVAR_CH4_OFI_RANK_BITS

• Aliases: - MVP_CH4_OFI_RANK_BITS

  • MPICH_CH4_OFI_RANK_BITS

• Description: - Specifies the number of bits that will be used for

  • matching the MPI rank. The default value is -1, indicating that no

  • value is set and that the default will be defined in the

  • ofi_types.h file.

• Default: -1

MPIR_CVAR_CH4_OFI_TAG_BITS

• Aliases: - MVP_CH4_OFI_TAG_BITS

  • MPICH_CH4_OFI_TAG_BITS

• Description: - Specifies the number of bits that will be used for

  • matching the user tag. The default value is -1, indicating that no

  • value is set and that the default will be defined in the

  • ofi_types.h file.

• Default: -1

MPIR_CVAR_CH4_OFI_MAJOR_VERSION

• Aliases: - MVP_CH4_OFI_MAJOR_VERSION

  • MPICH_CH4_OFI_MAJOR_VERSION

• Description: - Specifies the major version of the OFI library. The

  • default is the major version of the OFI library used with MPICH. If

  • using this CVAR, it is recommended that the user also specifies a

  • specific OFI provider.

• Default: -1

MPIR_CVAR_CH4_OFI_MINOR_VERSION

• Aliases: - MVP_CH4_OFI_MINOR_VERSION

  • MPICH_CH4_OFI_MINOR_VERSION

• Description: - Specifies the major version of the OFI library. The

  • default is the minor version of the OFI library used with MPICH. If

  • using this CVAR, it is recommended that the user also specifies a

  • specific OFI provider.

• Default: -1

MPIR_CVAR_CH4_OFI_MAX_RMA_SEP_CTX

• Aliases: - MVP_CH4_OFI_MAX_RMA_SEP_CTX

  • MPICH_CH4_OFI_MAX_RMA_SEP_CTX

• Description: - If set to positive, this CVAR specifies the maximum number

  • of transmit contexts RMA can utilize in a scalable endpoint. This

  • value is effective only when scalable endpoint is available,

  • otherwise it will be ignored.

• Default: 0

MPIR_CVAR_CH4_OFI_MAX_EAGAIN_RETRY

• Aliases: - MVP_CH4_OFI_MAX_EAGAIN_RETRY

  • MPICH_CH4_OFI_MAX_EAGAIN_RETRY

• Description: - If set to positive, this CVAR specifies the maximum number

  • of retries of an ofi operations before returning MPIX_ERR_EAGAIN.

  • This value is effective only when the communicator has the

  • MPI_OFI_set_eagain info hint set to true.

• Default: -1

MPIR_CVAR_CH4_OFI_NUM_AM_BUFFERS

• Aliases: - MVP_CH4_OFI_NUM_AM_BUFFERS

  • MPICH_CH4_OFI_NUM_AM_BUFFERS

• Description: - Specifies the number of buffers for receiving active

  • messages.

• Default: -1

MPIR_CVAR_CH4_OFI_NUM_OPTIMIZED_MEMORY_REGIONS

• Aliases: - MVP_CH4_OFI_NUM_OPTIMIZED_MEMORY_REGIONS

  • MPICH_CH4_OFI_NUM_OPTIMIZED_MEMORY_REGIONS

• Description: - Specifies the number of optimized memory regions supported

  • by the provider. An optimized memory region is used for

  • lower-overhead, unordered RMA operations. It uses a low-overhead RX

  • path and additionally, a low-overhead packet format may be used to

  • target an optimized memory region.

• Default: 0

MPIR_CVAR_CH4_OFI_RMA_PROGRESS_INTERVAL

• Aliases: - MVP_CH4_OFI_RMA_PROGRESS_INTERVAL

  • MPICH_CH4_OFI_RMA_PROGRESS_INTERVAL

• Description: - Specifies the interval for manually flushing RMA

  • operations when automatic progress is not enabled. It the

  • underlying OFI provider supports auto data progress, this value is

  • ignored. If the value is -1, this optimization will be turned off.

• Default: 100

MPIR_CVAR_CH4_OFI_RMA_IOVEC_MAX

• Aliases: - MVP_CH4_OFI_RMA_IOVEC_MAX

  • MPICH_CH4_OFI_RMA_IOVEC_MAX

• Description: - Specifies the maximum number of iovecs to allocate for RMA

  • operations to/from noncontiguous buffers.

• Default: 16384

MPIR_CVAR_CH4_OFI_EAGER_MAX_MSG_SIZE

• Aliases: - MVP_CH4_OFI_EAGER_MAX_MSG_SIZE

  • MPICH_CH4_OFI_EAGER_MAX_MSG_SIZE

• Description: - This cvar controls the message size at which OFI native

  • path switches from eager to rendezvous mode. It does not affect the

  • AM path eager limit. Having this gives a way to reliably test

  • native non-path. If the number is positive, OFI will init the

  • MPIDI_OFI_global.max_msg_size to the value of cvar. If the number

  • is negative, OFI will init the MPIDI_OFI_globa.max_msg_size using

  • whatever provider gives (which might be unlimited for socket

  • provider).

• Default: -1

MPIR_CVAR_CH4_OFI_MAX_NICS

• Aliases: - MVP_CH4_OFI_MAX_NICS

  • MPICH_CH4_OFI_MAX_NICS

• Description: - If set to positive number, this cvar determines the

  • maximum number of physical nics to use (if more than one is

  • available). If the number is -1, underlying netmod or shmmod

  • automatically uses an optimal number depending on what is detected

  • on the system up to the limit determined by MPIDI_MAX_NICS (in

  • ofi_types.h).

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_MULTI_NIC_STRIPING

• Aliases: - MVP_CH4_OFI_ENABLE_MULTI_NIC_STRIPING

  • MPICH_CH4_OFI_ENABLE_MULTI_NIC_STRIPING

• Description: - If true, this cvar enables striping of large messages

  • across multiple NICs.

• Default: 0

MPIR_CVAR_CH4_OFI_MULTI_NIC_STRIPING_THRESHOLD

• Aliases: - MVP_CH4_OFI_MULTI_NIC_STRIPING_THRESHOLD

  • MPICH_CH4_OFI_MULTI_NIC_STRIPING_THRESHOLD

• Description: - Striping will happen for message sizes beyond this

  • threshold.

• Default: 1048576

MPIR_CVAR_CH4_OFI_ENABLE_MULTI_NIC_HASHING

• Aliases: - MVP_CH4_OFI_ENABLE_MULTI_NIC_HASHING

  • MPICH_CH4_OFI_ENABLE_MULTI_NIC_HASHING

• Description: - Multi-NIC hashing means to use more than one NIC to send

  • and receive messages above a certain size. If set to positive

  • number, this feature will be turned on. If set to 0, this feature

  • will be turned off. If the number is -1, MPICH automatically

  • determines whether to use multi-nic hashing depending on what is

  • detected on the system (e.g., number of NICs available, number of

  • processes sharing the NICs).

• Default: 0

MPIR_CVAR_CH4_OFI_MULTIRECV_BUFFER_SIZE

• Aliases: - MVP_CH4_OFI_MULTIRECV_BUFFER_SIZE

  • MPICH_CH4_OFI_MULTIRECV_BUFFER_SIZE

• Description: - Controls the multirecv am buffer size. It is recommended

  • to match this to the hugepage size so that the buffer can be

  • allocated at the page boundary.

• Default: 2097152

MPIR_CVAR_OFI_USE_MIN_NICS

• Aliases: - MVP_OFI_USE_MIN_NICS

  • MPICH_OFI_USE_MIN_NICS

• Description: - If true and all nodes do not have the same number of NICs,

  • MPICH will fall back to using the fewest number of NICs instead of

  • returning an error.

• Default: 1

MPIR_CVAR_CH4_OFI_ENABLE_TRIGGERED

• Aliases: - MVP_CH4_OFI_ENABLE_TRIGGERED

  • MPICH_CH4_OFI_ENABLE_TRIGGERED

• Description: - If true, enable OFI triggered ops for MPI collectives.

• Default: -1

MPIR_CVAR_CH4_OFI_ENABLE_GPU_PIPELINE

• Aliases: - MVP_CH4_OFI_ENABLE_GPU_PIPELINE

  • MPICH_CH4_OFI_ENABLE_GPU_PIPELINE

• Description: - If true, enable pipeline for GPU data transfer. GPU

  • pipeline does not support non-contiguous datatypes or mixed buffer

  • types (i.e. GPU send buffer, host recv buffer). If GPU pipeline is

  • enabled, the unsupported scenarios will cause undefined behavior if

  • encountered.

• Default: 0

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_THRESHOLD

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_THRESHOLD

  • MPICH_CH4_OFI_GPU_PIPELINE_THRESHOLD

• Description: - This is the threshold to start using GPU pipeline.

• Default: 131072

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_BUFFER_SZ

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_BUFFER_SZ

  • MPICH_CH4_OFI_GPU_PIPELINE_BUFFER_SZ

• Description: - Specifies the buffer size (in bytes) for GPU pipeline data

  • transfer.

• Default: 1048576

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_NUM_BUFFERS_PER_CHUNK

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_NUM_BUFFERS_PER_CHUNK

  • MPICH_CH4_OFI_GPU_PIPELINE_NUM_BUFFERS_PER_CHUNK

• Description: - Specifies the number of buffers for GPU pipeline data

  • transfer in each block/chunk of the pool.

• Default: 32

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_MAX_NUM_BUFFERS

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_MAX_NUM_BUFFERS

  • MPICH_CH4_OFI_GPU_PIPELINE_MAX_NUM_BUFFERS

• Description: - Specifies the total number of buffers for GPU pipeline

  • data transfer

• Default: 32

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_D2H_ENGINE_TYPE

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_D2H_ENGINE_TYPE

  • MPICH_CH4_OFI_GPU_PIPELINE_D2H_ENGINE_TYPE

• Description: - Specifies the GPU engine type for GPU pipeline on the

  • sender side, default is MPL_GPU_ENGINE_TYPE_COMPUTE

• Default: 0

MPIR_CVAR_CH4_OFI_GPU_PIPELINE_H2D_ENGINE_TYPE

• Aliases: - MVP_CH4_OFI_GPU_PIPELINE_H2D_ENGINE_TYPE

  • MPICH_CH4_OFI_GPU_PIPELINE_H2D_ENGINE_TYPE

• Description: - Specifies the GPU engine type for GPU pipeline on the

  • receiver side, default is MPL_GPU_ENGINE_TYPE_COMPUTE

• Default: 0

MPIR_CVAR_MALLOC_ENABLE_MMAP

• Aliases: - MVP_MALLOC_ENABLE_MMAP

  • MPICH_MALLOC_ENABLE_MMAP

• Description: - Set to 0 to disable the use of MMAP by the standard memory

  • allocator. Doing so provides cache performance improvements for

  • most cases. Setting to 1 will return to the system default

  • behaviour.

• Default: 0

MPIR_CVAR_MALLOC_HEAP_STEP

• Aliases: - MVP_MALLOC_HEAP_STEP

  • MPICH_MALLOC_HEAP_STEP

• Description: - Sets the size by which the malloc program heap is expanded

  • by the memory allocator when new memory is required by the program.

  • A higher value will generally provide better cache performance, but

  • will result in a higher memory footprint. The program heap exists

  • on a per-processes basis. Setting this value to zero will use the

  • system default.

• Default: 32 * 1024 * 1024

MPIR_CVAR_CH4_OFI_PREF_NIC

• Aliases: - MVP_CH4_OFI_PREF_NIC

  • MPICH_CH4_OFI_PREF_NIC

• Description: - Accept the NIC value from a user

• Default: -1

MPIR_CVAR_CH4_OFI_DISABLE_INJECT_WRITE

• Aliases: - MVP_CH4_OFI_DISABLE_INJECT_WRITE

  • MPICH_CH4_OFI_DISABLE_INJECT_WRITE

• Description: - Avoid use fi_inject_write. For some provider, e.g.

  • tcp;ofi_rxm, inject write may break the synchronization.

• Default: 0

MPIR_CVAR_CH4_OFI_ENABLE_INJECT

• Aliases: - MVP_CH4_OFI_ENABLE_INJECT

  • MPICH_CH4_OFI_ENABLE_INJECT

• Description: - Set MPIR_CVAR_CH4_OFI_ENABLE_INJECT=0 to disable buffered

  • send for small messages. This may help avoid hang due to lack of

  • global progress.

• Default: 1

MPIR_CVAR_CH4_OFI_GPU_SEND_ENGINE_TYPE

• Aliases: - MVP_CH4_OFI_GPU_SEND_ENGINE_TYPE

  • MPICH_CH4_OFI_GPU_SEND_ENGINE_TYPE

• Description: - Specifies GPU engine type for GPU pt2pt on the sender

  • side.

  • compute - use a compute engine

  • copy_high_bandwidth - use a high-bandwidth copy engine

  • copy_low_latency - use a low-latency copy engine

  • yaksa - use Yaksa

• Default: MPIR_CVAR_CH4_OFI_GPU_SEND_ENGINE_TYPE_copy_low_latency

MPIR_CVAR_CH4_OFI_EAGER_THRESHOLD

• Aliases: - MVP_CH4_OFI_EAGER_THRESHOLD

  • MPICH_CH4_OFI_EAGER_THRESHOLD

• Description: - Messages below MPIR_CVAR_CH4_OFI_EAGER_THRESHOLD will be

  • sent eagerly using fi_tagged interfaces. Messages above the

  • threshold will perform an MPICH-level rendezvous handshake before

  • sending the data. If set to -1, MPICH will only perform rendezvous

  • for messages larger than the provider max_msg_size. Note the MPICH

  • eager/rendezvous threshold is independent of any internal libfabric

  • provider threshold.

• Default: -1

MPIR_CVAR_UCX_DT_RECV

• Aliases: - MVP_UCX_DT_RECV

  • MPICH_UCX_DT_RECV

• Description: - Variable to select method for receiving noncontiguous data

  • true - - - Use UCX datatype with pack/unpack callbacks

  • false - - MPICH will decide to pack/unpack at

  • completion or use IOVs

  • based on the datatype

• Default: 0

MPIR_CVAR_CH4_CMA_ENABLE

• Aliases: - MVP_CH4_CMA_ENABLE

  • MPICH_CH4_CMA_ENABLE

• Description: - Set to 1 to manually enable CMA. It is disabled by default

  • because the CMA requires the ptrace_scope permission, which is

  • often disabled.

• Default: 1

MPIR_CVAR_CH4_IPC_CMA_P2P_THRESHOLD

• Aliases: - MVP_CH4_IPC_CMA_P2P_THRESHOLD

  • MPICH_CH4_IPC_CMA_P2P_THRESHOLD

• Description: - If a send message size is greater than or equal to

  • MPIR_CVAR_CH4_IPC_CMA_P2P_THRESHOLD (in bytes), then enable

  • CMA-based single copy protocol for intranode communication. The

  • environment variable is valid only when the CMA submodule is

  • enabled.

• Default: 16384

MPIR_CVAR_CH4_IPC_RNDV_PROTOCOL

• Aliases: - MVP_CH4_IPC_RNDV_PROTOCOL

  • MPICH_CH4_IPC_RNDV_PROTOCOL

• Description: - Variable to select the RNDV protocol.

  • auto - Default RNDV Protocol that enable COOP automatically

  • rget - RNDV RGET Protocol

  • rput - RNDV RPUT Protocol

  • coop - RNDV COOP Protocol

• Default: MPIR_CVAR_CH4_IPC_RNDV_PROTOCOL_rget

MPIR_CVAR_CH4_IPC_CMA_COOP_THRESHOLD

• Aliases: - MVP_CH4_IPC_CMA_COOP_THRESHOLD

  • MPICH_CH4_IPC_CMA_COOP_THRESHOLD

• Description: - If a send message size is greater than or equal to

  • MPIR_CVAR_CH4_CMA_COOP_THRESHOLD (in bytes), then enable CMA-based

  • COOP rndv protocol for intra-node communication. Messages below

  • this threshold will use either RPUT or RGET protocol as set by

  • MPIR_CVAR_CH4_IPC_RNDV_PROTOCOL.

• Default: 16384

MPIR_CVAR_CH4_IPC_GPU_HANDLE_CACHE

• Aliases: - MVP_CH4_IPC_GPU_HANDLE_CACHE

  • MPICH_CH4_IPC_GPU_HANDLE_CACHE

• Description: - By default, we will cache ipc handles using the

  • specialized cache mechanism. If the

  • gpu-specific backend does not implement a specialized cache, then

  • we will fallback to

  • the generic cache mechanism. Users can optionally force the generic

  • cache mechanism or

  • disable ipc caching entirely.

  • generic - use the cache mechanism in the generic layer

  • specialized - use the cache mechanism in a gpu-specific mpl layer

  • (if applicable)

  • disabled - disable caching completely

• Default: MPIR_CVAR_CH4_IPC_GPU_HANDLE_CACHE_specialized

MPIR_CVAR_CH4_IPC_GPU_MAX_CACHE_ENTRIES

• Aliases: - MVP_CH4_IPC_GPU_MAX_CACHE_ENTRIES

  • MPICH_CH4_IPC_GPU_MAX_CACHE_ENTRIES

• Description: - The maximum number of entries to hold per device in the

  • cache containing IPC mapped buffers. When an entry is evicted, the

  • corresponding IPC handle is closed. This value is relevant only

  • when MPIR_CVAR_CH4_IPC_GPU_CACHE_SIZE=limited.

• Default: 16

MPIR_CVAR_CH4_IPC_GPU_CACHE_SIZE

• Aliases: - MVP_CH4_IPC_GPU_CACHE_SIZE

  • MPICH_CH4_IPC_GPU_CACHE_SIZE

• Description: - The behavior of the cache containing IPC mapped buffers.

  • unlimited - don’t restrict the cache size

  • limited - limit the cache size based on

  • MPIR_CVAR_CH4_IPC_GPU_MAX_CACHE_ENTRIES

  • disabled - don’t cache mapped IPC buffers

• Default: MPIR_CVAR_CH4_IPC_GPU_CACHE_SIZE_limited

MPIR_CVAR_CH4_IPC_GPU_P2P_THRESHOLD

• Aliases: - MVP_CH4_IPC_GPU_P2P_THRESHOLD

  • MPICH_CH4_IPC_GPU_P2P_THRESHOLD

• Description: - If a send message size is greater than or equal to

  • MPIR_CVAR_CH4_IPC_GPU_P2P_THRESHOLD (in bytes), then enable

  • GPU-based single copy protocol for intranode communication. The

  • environment variable is valid only when then GPU IPC shmmod is

  • enabled.

• Default: 1048576

MPIR_CVAR_CH4_IPC_ZE_SHAREABLE_HANDLE

• Aliases: - MVP_CH4_IPC_ZE_SHAREABLE_HANDLE

  • MPICH_CH4_IPC_ZE_SHAREABLE_HANDLE

• Description: - Variable to select implementation for ZE shareable IPC

  • handle

  • pidfd - use pidfd_getfd syscall to implement shareable IPC handle

  • drmfd - force to use device fd-based shareable IPC handle

• Default: MPIR_CVAR_CH4_IPC_ZE_SHAREABLE_HANDLE_drmfd

MPIR_CVAR_CH4_IPC_GPU_ENGINE_TYPE

• Aliases: - MVP_CH4_IPC_GPU_ENGINE_TYPE

  • MPICH_CH4_IPC_GPU_ENGINE_TYPE

• Description: - By default, select engine type automatically

  • auto - select automatically

  • compute - use compute engine

  • copy_high_bandwidth - use high-bandwidth copy engine

  • copy_low_latency - use low-latency copy engine

• Default: MPIR_CVAR_CH4_IPC_GPU_ENGINE_TYPE_auto

MPIR_CVAR_CH4_IPC_GPU_READ_WRITE_PROTOCOL

• Aliases: - MVP_CH4_IPC_GPU_READ_WRITE_PROTOCOL

  • MPICH_CH4_IPC_GPU_READ_WRITE_PROTOCOL

• Description: - By default, use read protocol.

  • auto - select automatically

  • read - use read protocol

  • write - use write protocol if remote device is visible

• Default: MPIR_CVAR_CH4_IPC_GPU_READ_WRITE_PROTOCOL_read

MPIR_CVAR_CH4_IPC_GPU_RMA_ENGINE_TYPE

• Aliases: - MVP_CH4_IPC_GPU_RMA_ENGINE_TYPE

  • MPICH_CH4_IPC_GPU_RMA_ENGINE_TYPE

• Description: - By default, select engine type automatically

  • yaksa - don’t select, use yaksa

  • auto - select automatically

  • compute - use compute engine

  • copy_high_bandwidth - use high-bandwidth copy engine

  • copy_low_latency - use low-latency copy engine

• Default: MPIR_CVAR_CH4_IPC_GPU_RMA_ENGINE_TYPE_auto

MPIR_CVAR_CH4_IPC_MAP_REPEAT_ADDR

• Aliases: - MVP_CH4_IPC_MAP_REPEAT_ADDR

  • MPICH_CH4_IPC_MAP_REPEAT_ADDR

• Description: - If an address is used more than once in the last ten send

  • operations, map it for IPC use even if it is below the IPC

  • threshold.

• Default: 1

MPIR_CVAR_CH4_XPMEM_ENABLE

• Aliases: - MVP_CH4_XPMEM_ENABLE

  • MPICH_CH4_XPMEM_ENABLE

• Description: - To manually disable XPMEM set to 0. The environment

  • variable is valid only when the XPMEM submodule is enabled.

• Default: 1

MPIR_CVAR_CH4_IPC_XPMEM_P2P_THRESHOLD

• Aliases: - MVP_CH4_IPC_XPMEM_P2P_THRESHOLD

  • MPICH_CH4_IPC_XPMEM_P2P_THRESHOLD

• Description: - If a send message size is greater than or equal to

  • MPIR_CVAR_CH4_IPC_XPMEM_P2P_THRESHOLD (in bytes), then enable

  • XPMEM-based single copy protocol for intranode communication. The

  • environment variable is valid only when the XPMEM submodule is

  • enabled.

• Default: 1024

MPIR_CVAR_BCAST_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_BCAST_POSIX_INTRA_ALGORITHM

  • MPICH_BCAST_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node bcast

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

  • ipc_read - Uses read-based collective with ipc

• Default: MPIR_CVAR_BCAST_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_IBCAST_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_IBCAST_POSIX_INTRA_ALGORITHM

  • MPICH_IBCAST_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node bcast

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_IBCAST_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_REDUCE_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_REDUCE_POSIX_INTRA_ALGORITHM

  • MPICH_REDUCE_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node reduce

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_REDUCE_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_IREDUCE_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_IREDUCE_POSIX_INTRA_ALGORITHM

  • MPICH_IREDUCE_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node reduce

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_IREDUCE_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLREDUCE_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_ALLREDUCE_POSIX_INTRA_ALGORITHM

  • MPICH_ALLREDUCE_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node allreduce

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_ALLREDUCE_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_BARRIER_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_BARRIER_POSIX_INTRA_ALGORITHM

  • MPICH_BARRIER_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node barrier

  • mpir - - Fallback to MPIR collectives

  • release_gather - Force shm optimized algo using release, gather

  • primitives

  • auto - Internal algorithm selection (can be overridden with

  • MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE)

• Default: MPIR_CVAR_BARRIER_POSIX_INTRA_ALGORITHM_auto

MPIR_CVAR_ALLTOALL_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_ALLTOALL_POSIX_INTRA_ALGORITHM

  • MPICH_ALLTOALL_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node alltoall

  • mpir - - Fallback to MPIR collectives (default)

  • ipc_read - Uses read-based collective with ipc

• Default: MPIR_CVAR_ALLTOALL_POSIX_INTRA_ALGORITHM_mpir

MPIR_CVAR_ALLGATHER_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_ALLGATHER_POSIX_INTRA_ALGORITHM

  • MPICH_ALLGATHER_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node allgather

  • mpir - - Fallback to MPIR collectives (default)

  • ipc_read - Uses read-based collective with ipc

• Default: MPIR_CVAR_ALLGATHER_POSIX_INTRA_ALGORITHM_mpir

MPIR_CVAR_ALLGATHERV_POSIX_INTRA_ALGORITHM

• Aliases: - MVP_ALLGATHERV_POSIX_INTRA_ALGORITHM

  • MPICH_ALLGATHERV_POSIX_INTRA_ALGORITHM

• Description: - Variable to select algorithm for intra-node allgatherv

  • mpir - - Fallback to MPIR collectives (default)

  • ipc_read - Uses read-based collective with ipc

• Default: MPIR_CVAR_ALLGATHERV_POSIX_INTRA_ALGORITHM_mpir

MPIR_CVAR_POSIX_POLL_FREQUENCY

• Aliases: - MVP_POSIX_POLL_FREQUENCY

  • MPICH_POSIX_POLL_FREQUENCY

• Description: - This cvar sets the number of loops before the yield

  • function is called. A value of 0 disables yielding.

• Default: 1000

MPIR_CVAR_BCAST_IPC_READ_MSG_SIZE_THRESHOLD

• Aliases: - MVP_BCAST_IPC_READ_MSG_SIZE_THRESHOLD

  • MPICH_BCAST_IPC_READ_MSG_SIZE_THRESHOLD

• Description: - Use gpu ipc read bcast only when the message size is

  • larger than this threshold.

• Default: 256

MPIR_CVAR_ALLTOALL_IPC_READ_MSG_SIZE_THRESHOLD

• Aliases: - MVP_ALLTOALL_IPC_READ_MSG_SIZE_THRESHOLD

  • MPICH_ALLTOALL_IPC_READ_MSG_SIZE_THRESHOLD

• Description: - Use gpu ipc read alltoall only when the message size is

  • larger than this threshold.

• Default: 256

MPIR_CVAR_ALLGATHER_IPC_READ_MSG_SIZE_THRESHOLD

• Aliases: - MVP_ALLGATHER_IPC_READ_MSG_SIZE_THRESHOLD

  • MPICH_ALLGATHER_IPC_READ_MSG_SIZE_THRESHOLD

• Description: - Use gpu ipc read allgather only when the message size is

  • larger than this threshold.

• Default: 256

MPIR_CVAR_ALLGATHERV_IPC_READ_MSG_SIZE_THRESHOLD

• Aliases: - MVP_ALLGATHERV_IPC_READ_MSG_SIZE_THRESHOLD

  • MPICH_ALLGATHERV_IPC_READ_MSG_SIZE_THRESHOLD

• Description: - Use gpu ipc read allgatherv only when the message size is

  • larger than this threshold.

• Default: 256

MPIR_CVAR_POSIX_NUM_COLLS_THRESHOLD

• Aliases: - MVP_POSIX_NUM_COLLS_THRESHOLD

  • MPICH_POSIX_NUM_COLLS_THRESHOLD

• Description: - Use posix optimized collectives (release_gather) only when

  • the total number of Bcast, Reduce, Barrier, and Allreduce calls on

  • the node level communicator is more than this threshold.

• Default: 5

MPIR_CVAR_CH4_SHM_POSIX_EAGER

• Aliases: - MVP_CH4_SHM_POSIX_EAGER

  • MPICH_CH4_SHM_POSIX_EAGER

• Description: - If non-empty, this cvar specifies which shm posix eager

  • module to use

• Default: “”

MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE

• Aliases: - MVP_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE

  • MPICH_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE

• Description: - Defines the location of tuning file.

• Default: “”

MPIR_CVAR_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE_GPU

• Aliases: - MVP_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE_GPU

  • MPICH_CH4_POSIX_COLL_SELECTION_TUNING_JSON_FILE_GPU

• Description: - Defines the location of tuning file for GPU.

• Default: “”

MPIR_CVAR_CH4_SHM_POSIX_TOPO_ENABLE

• Aliases: - MVP_CH4_SHM_POSIX_TOPO_ENABLE

  • MPICH_CH4_SHM_POSIX_TOPO_ENABLE

• Description: - Controls topology-aware communication in POSIX.

• Default: 0

MPIR_CVAR_CH4_SHM_POSIX_IQUEUE_NUM_CELLS

• Aliases: - MVP_CH4_SHM_POSIX_IQUEUE_NUM_CELLS

  • MPICH_CH4_SHM_POSIX_IQUEUE_NUM_CELLS

• Description: - The number of cells used for the depth of the iqueue.

• Default: 64

MPIR_CVAR_CH4_SHM_POSIX_IQUEUE_CELL_SIZE

• Aliases: - MVP_CH4_SHM_POSIX_IQUEUE_CELL_SIZE

  • MPICH_CH4_SHM_POSIX_IQUEUE_CELL_SIZE

• Description: - Size of each cell.

• Default: 16384

MPIR_CVAR_CH4_MVP_SHM_POSIX_NUM_CELLS

• Aliases: - MVP_CH4_MVP_SHM_POSIX_NUM_CELLS

  • MPICH_CH4_MVP_SHM_POSIX_NUM_CELLS

• Description: - The number of cells used per sender

• Default: 128

MPIR_CVAR_CH4_MVP_SHM_POSIX_CELL_SIZE

• Aliases: - MVP_CH4_MVP_SHM_POSIX_CELL_SIZE

  • MPICH_CH4_MVP_SHM_POSIX_CELL_SIZE

• Description: - Size of each cell.

• Default: 16384

MPIR_CVAR_COLL_SHM_LIMIT_PER_NODE

• Aliases: - MVP_COLL_SHM_LIMIT_PER_NODE

  • MPICH_COLL_SHM_LIMIT_PER_NODE

• Description: - Maximum shared memory created per node for optimized

  • intra-node collectives (in KB)

• Default: 65536

MPIR_CVAR_BCAST_INTRANODE_BUFFER_TOTAL_SIZE

• Aliases: - MVP_BCAST_INTRANODE_BUFFER_TOTAL_SIZE

  • MPICH_BCAST_INTRANODE_BUFFER_TOTAL_SIZE

• Description: - Total size of the bcast buffer (in bytes)

• Default: 32768

MPIR_CVAR_BCAST_INTRANODE_NUM_CELLS

• Aliases: - MVP_BCAST_INTRANODE_NUM_CELLS

  • MPICH_BCAST_INTRANODE_NUM_CELLS

• Description: - Number of cells the bcast buffer is divided into

• Default: 4

MPIR_CVAR_REDUCE_INTRANODE_BUFFER_TOTAL_SIZE

• Aliases: - MVP_REDUCE_INTRANODE_BUFFER_TOTAL_SIZE

  • MPICH_REDUCE_INTRANODE_BUFFER_TOTAL_SIZE

• Description: - Total size of the reduce buffer per rank (in bytes)

• Default: 32768

MPIR_CVAR_REDUCE_INTRANODE_NUM_CELLS

• Aliases: - MVP_REDUCE_INTRANODE_NUM_CELLS

  • MPICH_REDUCE_INTRANODE_NUM_CELLS

• Description: - Number of cells the reduce buffer is divided into, for

  • each rank

• Default: 4

MPIR_CVAR_BCAST_INTRANODE_TREE_KVAL

• Aliases: - MVP_BCAST_INTRANODE_TREE_KVAL

  • MPICH_BCAST_INTRANODE_TREE_KVAL

• Description: - K value for the kary/knomial tree for intra-node bcast

• Default: 64

MPIR_CVAR_BCAST_INTRANODE_TREE_TYPE

• Aliases: - MVP_BCAST_INTRANODE_TREE_TYPE

  • MPICH_BCAST_INTRANODE_TREE_TYPE

• Description: - Tree type for intra-node bcast tree kary - kary tree

  • type knomial_1 - knomial_1 tree type (ranks are added in order from

  • the left side) knomial_2 - knomial_2 tree type (ranks are added in

  • order from the right side) knomial_2 is only supported with non

  • topology aware trees.

• Default: “kary”

MPIR_CVAR_REDUCE_INTRANODE_MSG_SIZE_THRESHOLD

• Aliases: - MVP_REDUCE_INTRANODE_MSG_SIZE_THRESHOLD

  • MPICH_REDUCE_INTRANODE_MSG_SIZE_THRESHOLD

• Description: - MPIR_CVAR_REDUCE_INTRANODE_TREE_KVAL and

  • MPIR_CVAR_REDUCE_INTRANODE_TREE_TYPE are used when the message size

  • is smaller than or equal to this threshold;

  • MPIR_CVAR_REDUCE_INTRANODE_TREE_KVAL_LARGE and

  • MPIR_CVAR_REDUCE_INTRANODE_TREE_TYPE_LARGE are used when the

  • message size is larger than this threshold.

• Default: 2048

MPIR_CVAR_REDUCE_INTRANODE_TREE_KVAL

• Aliases: - MVP_REDUCE_INTRANODE_TREE_KVAL

  • MPICH_REDUCE_INTRANODE_TREE_KVAL

• Description: - K value for the kary/knomial tree for intra-node reduce

• Default: 4

MPIR_CVAR_REDUCE_INTRANODE_TREE_KVAL_LARGE

• Aliases: - MVP_REDUCE_INTRANODE_TREE_KVAL_LARGE

  • MPICH_REDUCE_INTRANODE_TREE_KVAL_LARGE

• Description: - K value for the kary/knomial tree for intra-node reduce.

  • Used for large messages.

• Default: 2

MPIR_CVAR_REDUCE_INTRANODE_TREE_TYPE

• Aliases: - MVP_REDUCE_INTRANODE_TREE_TYPE

  • MPICH_REDUCE_INTRANODE_TREE_TYPE

• Description: - Tree type for intra-node reduce tree kary - kary tree

  • type knomial_1 - knomial_1 tree type (ranks are added in order from

  • the left side) knomial_2 - knomial_2 tree type (ranks are added in

  • order from the right side) knomial_2 is only supported with non

  • topology aware trees.

• Default: “kary”

MPIR_CVAR_REDUCE_INTRANODE_TREE_TYPE_LARGE

• Aliases: - MVP_REDUCE_INTRANODE_TREE_TYPE_LARGE

  • MPICH_REDUCE_INTRANODE_TREE_TYPE_LARGE

• Description: - Tree type for intra-node reduce tree. Used for large

  • messages. kary - kary tree type knomial_1 - knomial_1 tree

  • type (ranks are added in order from the left side) knomial_2 -

  • knomial_2 tree type (ranks are added in order from the right side)

  • knomial_2 is only supported with non topology aware trees.

• Default: “kary”

MPIR_CVAR_ENABLE_INTRANODE_TOPOLOGY_AWARE_TREES

• Aliases: - MVP_ENABLE_INTRANODE_TOPOLOGY_AWARE_TREES

  • MPICH_ENABLE_INTRANODE_TOPOLOGY_AWARE_TREES

• Description: - Enable collective specific intra-node trees which leverage

  • the memory hierarchy of a machine. Depends on hwloc to extract the

  • binding information of each rank. Pick a leader rank per package

  • (socket), then create a per_package tree for ranks on a same

  • package, package leaders tree for package leaders. For Bcast -

  • Assemble the per_package and package_leaders tree in such a way

  • that leaders interact among themselves first before interacting

  • with package local ranks. Both the package_leaders and per_package

  • trees are left skewed (children are added from left to right, first

  • child to be added is the first one to be processed in traversal)

  • For Reduce - Assemble the per_package and package_leaders tree in

  • such a way that a leader rank interacts with its package local

  • ranks first, then with the other package leaders. Both the

  • per_package and package_leaders tree is right skewed (children are

  • added in reverse order, first child to be added is the last one to

  • be processed in traversal) The tree radix and tree type of

  • package_leaders and per_package tree is

  • MPIR_CVAR_BCAST{REDUCE}_INTRANODE_TREE_KVAL and

  • MPIR_CVAR_BCAST{REDUCE}_INTRANODE_TREE_TYPE respectively for bast

  • and reduce. But of as now topology aware trees are only kary and

  • knomial_1. knomial_2 is not implemented.

• Default: 1

MPIR_CVAR_BARRIER_COMPOSITION

• Aliases: - MVP_BARRIER_COMPOSITION

  • MPICH_BARRIER_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Barrier 0

  • Auto selection 1 NM + SHM 2 NM only

• Default: 0

MPIR_CVAR_BCAST_COMPOSITION

• Aliases: - MVP_BCAST_COMPOSITION

  • MPICH_BCAST_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Bcast 0

  • Auto selection 1 NM + SHM with explicit send-recv between rank 0

  • and root 2 NM + SHM without the explicit send-recv 3 NM only

• Default: 0

MPIR_CVAR_ALLREDUCE_COMPOSITION

• Aliases: - MVP_ALLREDUCE_COMPOSITION

  • MPICH_ALLREDUCE_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Allreduce

  • 0 Auto selection 1 NM + SHM with reduce + bcast 2 NM only

  • composition 3 SHM only composition 4 Multi leaders based inter node

  • • intra node composition

• Default: 0

MPIR_CVAR_ALLGATHER_COMPOSITION

• Aliases: - MVP_ALLGATHER_COMPOSITION

  • MPICH_ALLGATHER_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Allgather

  • 0 Auto selection 1 Multi leaders based inter node + intra node

  • composition 2 NM only composition

• Default: 0

MPIR_CVAR_ALLTOALL_COMPOSITION

• Aliases: - MVP_ALLTOALL_COMPOSITION

  • MPICH_ALLTOALL_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Alltoall

  • 0 Auto selection 1 Multi leaders based inter node + intra node

  • composition 2 NM only composition

• Default: 0

MPIR_CVAR_REDUCE_COMPOSITION

• Aliases: - MVP_REDUCE_COMPOSITION

  • MPICH_REDUCE_COMPOSITION

• Description: - Select composition (inter_node + intra_node) for Reduce 0

  • Auto selection 1 NM + SHM with explicit send-recv between rank 0

  • and root 2 NM + SHM without the explicit send-recv 3 NM only

• Default: 0

MPIR_CVAR_ALLTOALL_SHM_PER_RANK

• Aliases: - MVP_ALLTOALL_SHM_PER_RANK

  • MPICH_ALLTOALL_SHM_PER_RANK

• Description: - Shared memory region per rank for multi-leaders based

  • composition for MPI_Alltoall (in bytes)

• Default: 4096

MPIR_CVAR_ALLGATHER_SHM_PER_RANK

• Aliases: - MVP_ALLGATHER_SHM_PER_RANK

  • MPICH_ALLGATHER_SHM_PER_RANK

• Description: - Shared memory region per rank for multi-leaders based

  • composition for MPI_Allgather (in bytes)

• Default: 4096

MPIR_CVAR_NUM_MULTI_LEADS

• Aliases: - MVP_NUM_MULTI_LEADS

  • MPICH_NUM_MULTI_LEADS

• Description: - Number of leader ranks per node to be used for

  • multi-leaders based collective algorithms

• Default: 4

MPIR_CVAR_ALLREDUCE_SHM_PER_LEADER

• Aliases: - MVP_ALLREDUCE_SHM_PER_LEADER

  • MPICH_ALLREDUCE_SHM_PER_LEADER

• Description: - Shared memory region per node-leader for multi-leaders

  • based composition for MPI_Allreduce (in bytes) If it is undefined

  • by the user, it is set to the message size of the first call to the

  • algorithm. Max shared memory size is limited to 4MB.

• Default: -1

MPIR_CVAR_ALLREDUCE_CACHE_PER_LEADER

• Aliases: - MVP_ALLREDUCE_CACHE_PER_LEADER

  • MPICH_ALLREDUCE_CACHE_PER_LEADER

• Description: - Amount of data reduced in allreduce delta composition’s

  • reduce local step (in bytes). Smaller msg size per leader avoids

  • cache misses and improves performance. Experiments indicate 512 to

  • be the best value.

• Default: 512

MPIR_CVAR_ALLREDUCE_LOCAL_COPY_OFFSETS

• Aliases: - MVP_ALLREDUCE_LOCAL_COPY_OFFSETS

  • MPICH_ALLREDUCE_LOCAL_COPY_OFFSETS

• Description: - number of offsets in the allreduce delta composition’s

  • local copy The value of 2 performed the best in our 2 NIC test

  • cases.

• Default: 2

MPIR_CVAR_CH4_NETMOD

• Aliases: - MVP_CH4_NETMOD

  • MPICH_CH4_NETMOD

• Description: - If non-empty, this cvar specifies which network module to

  • use

• Default: “”

MPIR_CVAR_CH4_SHM

• Aliases: - MVP_CH4_SHM

  • MPICH_CH4_SHM

• Description: - If non-empty, this cvar specifies which shm module to use

• Default: “”

MPIR_CVAR_CH4_ROOTS_ONLY_PMI

• Aliases: - MVP_CH4_ROOTS_ONLY_PMI

  • MPICH_CH4_ROOTS_ONLY_PMI

• Description: - Enables an optimized business card exchange over PMI for

  • node root processes only.

• Default: 1

MPIR_CVAR_CH4_RUNTIME_CONF_DEBUG

• Aliases: - MVP_CH4_RUNTIME_CONF_DEBUG

  • MPICH_CH4_RUNTIME_CONF_DEBUG

• Description: - If enabled, CH4-level runtime configurations are printed

  • out

• Default: 0

MPIR_CVAR_CH4_MT_MODEL

• Aliases: - MVP_CH4_MT_MODEL

  • MPICH_CH4_MT_MODEL

• Description: - Specifies the CH4 multi-threading model. Possible values

  • are: direct (default) lockless

• Default: “”

MPIR_CVAR_CH4_NUM_VCIS

• Aliases: - MVP_CH4_NUM_VCIS

  • MPICH_CH4_NUM_VCIS

• Description: - Sets the number of VCIs to be implicitly used (should be a

  • subset of MPIDI_CH4_MAX_VCIS).

• Default: 1

MPIR_CVAR_CH4_RESERVE_VCIS

• Aliases: - MVP_CH4_RESERVE_VCIS

  • MPICH_CH4_RESERVE_VCIS

• Description: - Sets the number of VCIs that user can explicitly allocate

  • (should be a subset of MPIDI_CH4_MAX_VCIS).

• Default: 0

MPIR_CVAR_CH4_COLL_SELECTION_TUNING_JSON_FILE

• Aliases: - MVP_CH4_COLL_SELECTION_TUNING_JSON_FILE

  • MPICH_CH4_COLL_SELECTION_TUNING_JSON_FILE

• Description: - Defines the location of tuning file.

• Default: “”

MPIR_CVAR_CH4_COLL_SELECTION_TUNING_JSON_FILE_GPU

• Aliases: - MVP_CH4_COLL_SELECTION_TUNING_JSON_FILE_GPU

  • MPICH_CH4_COLL_SELECTION_TUNING_JSON_FILE_GPU

• Description: - Defines the location of tuning file for GPU.

• Default: “”

MPIR_CVAR_CH4_IOV_DENSITY_MIN

• Aliases: - MVP_CH4_IOV_DENSITY_MIN

  • MPICH_CH4_IOV_DENSITY_MIN

• Description: - Defines the threshold of high-density datatype. The

  • density is calculated by (datatype_size /

  • datatype_num_contig_blocks).

• Default: 16384

MPIR_CVAR_CH4_PACK_BUFFER_SIZE

• Aliases: - MVP_CH4_PACK_BUFFER_SIZE

  • MPICH_CH4_PACK_BUFFER_SIZE

• Description: - Specifies the number of buffers for packing/unpacking

  • active messages in each block of the pool. The size here should be

  • greater or equal to the max of the eager buffer limit of SHM and

  • NETMOD.

• Default: 16384

MPIR_CVAR_CH4_NUM_PACK_BUFFERS_PER_CHUNK

• Aliases: - MVP_CH4_NUM_PACK_BUFFERS_PER_CHUNK

  • MPICH_CH4_NUM_PACK_BUFFERS_PER_CHUNK

• Description: - Specifies the number of buffers for packing/unpacking

  • active messages in each block of the pool.

• Default: 64

MPIR_CVAR_CH4_MAX_NUM_PACK_BUFFERS

• Aliases: - MVP_CH4_MAX_NUM_PACK_BUFFERS

  • MPICH_CH4_MAX_NUM_PACK_BUFFERS

• Description: - Specifies the max number of buffers for packing/unpacking

  • buffers in the pool. Use 0 for unlimited.

• Default: 0

MPIR_CVAR_CH4_GPU_COLL_SWAP_BUFFER_SZ

• Aliases: - MVP_CH4_GPU_COLL_SWAP_BUFFER_SZ

  • MPICH_CH4_GPU_COLL_SWAP_BUFFER_SZ

• Description: - Specifies the buffer size (in bytes) for GPU collectives

  • data transfer.

• Default: 1048576

MPIR_CVAR_CH4_GPU_COLL_NUM_BUFFERS_PER_CHUNK

• Aliases: - MVP_CH4_GPU_COLL_NUM_BUFFERS_PER_CHUNK

  • MPICH_CH4_GPU_COLL_NUM_BUFFERS_PER_CHUNK

• Description: - Specifies the number of buffers for GPU collectives data

  • transfer in each block/chunk of the pool.

• Default: 1

MPIR_CVAR_CH4_GPU_COLL_MAX_NUM_BUFFERS

• Aliases: - MVP_CH4_GPU_COLL_MAX_NUM_BUFFERS

  • MPICH_CH4_GPU_COLL_MAX_NUM_BUFFERS

• Description: - Specifies the total number of buffers for GPU collectives

  • data transfer.

• Default: 256

MPIR_CVAR_CH4_GLOBAL_PROGRESS

• Aliases: - MVP_CH4_GLOBAL_PROGRESS

  • MPICH_CH4_GLOBAL_PROGRESS

• Description: - If on, poll global progress every once a while. With

  • per-vci configuration, turning global progress off may improve the

  • threading performance.

• Default: 1

MPIR_CVAR_CH4_COMM_CONNECT_TIMEOUT

• Aliases: - MVP_CH4_COMM_CONNECT_TIMEOUT

  • MPICH_CH4_COMM_CONNECT_TIMEOUT

• Description: - The default time out period in seconds for a connection

  • attempt to the server communicator where the named port exists but

  • no pending accept. User can change the value for a specified

  • connection through its info argument.

• Default: 180

MPIR_CVAR_CH4_ENABLE_STREAM_WORKQ

• Aliases: - MVP_CH4_ENABLE_STREAM_WORKQ

  • MPICH_CH4_ENABLE_STREAM_WORKQ

• Description: - Enable stream enqueue operations via stream work queue.

  • Requires progress thread on the corresponding MPIX stream.

  • Reference: MPIX_Stream_progress and MPIX_Start_progress_thread.

• Default: 0

MPIR_CVAR_CH4_RMA_MEM_EFFICIENT

• Aliases: - MVP_CH4_RMA_MEM_EFFICIENT

  • MPICH_CH4_RMA_MEM_EFFICIENT

• Description: - If true, memory-saving mode is on, per-target object is

  • released at the epoch end call. If false, performance-efficient

  • mode is on, all allocated target objects are cached and freed at

  • win_finalize.

• Default: 0

MPIR_CVAR_CH4_RMA_ENABLE_DYNAMIC_AM_PROGRESS

• Aliases: - MVP_CH4_RMA_ENABLE_DYNAMIC_AM_PROGRESS

  • MPICH_CH4_RMA_ENABLE_DYNAMIC_AM_PROGRESS

• Description: - If true, allows RMA synchronization calls to dynamically

  • reduce the frequency of internal progress polling for incoming RMA

  • active messages received on the target process. The RMA

  • synchronization call initially polls progress with a low frequency

  • (defined by MPIR_CVAR_CH4_RMA_AM_PROGRESS_LOW_FREQ_INTERVAL) to

  • reduce synchronization overhead. Once any RMA active message has

  • been received, it will always poll progress once at every

  • synchronization call to ensure prompt target-side progress.

  • Effective only for passive target synchronization

  • MPI_Win_flush{_all} and MPI_Win_flush_local{_all}.

• Default: 0

MPIR_CVAR_CH4_RMA_AM_PROGRESS_INTERVAL

• Aliases: - MVP_CH4_RMA_AM_PROGRESS_INTERVAL

  • MPICH_CH4_RMA_AM_PROGRESS_INTERVAL

• Description: - Specifies a static interval of progress polling for

  • incoming RMA active messages received on the target process.

  • Effective only for passive-target synchronization

  • MPI_Win_flush{_all} and MPI_Win_flush_local{_all}. Interval

  • indicates the number of performed flush calls before polling. It is

  • counted globally across all windows. Invalid when

  • MPIR_CVAR_CH4_RMA_ENABLE_DYNAMIC_AM_PROGRESS is true.

• Default: 1

MPIR_CVAR_CH4_RMA_AM_PROGRESS_LOW_FREQ_INTERVAL

• Aliases: - MVP_CH4_RMA_AM_PROGRESS_LOW_FREQ_INTERVAL

  • MPICH_CH4_RMA_AM_PROGRESS_LOW_FREQ_INTERVAL

• Description: - Specifies the interval of progress polling with low

  • frequency for incoming RMA active message received on the target

  • process. Effective only for passive-target synchronization

  • MPI_Win_flush{_all} and MPI_Win_flush_local{_all}. Interval

  • indicates the number of performed flush calls before polling. It is

  • counted globally across all windows. Used when

  • MPIR_CVAR_CH4_RMA_ENABLE_DYNAMIC_AM_PROGRESS is true.

• Default: 100

MPIR_CVAR_PT2PT_JSON_TUNING_FILE

• Aliases: - MVP_PT2PT_JSON_TUNING_FILE

  • MPICH_PT2PT_JSON_TUNING_FILE

• Description: - If non-empty, this cvar specifies a file for

  • architecture-specific tuning

• Default: “”

MPIR_CVAR_GENQ_SHMEM_POOL_FREE_QUEUE_SENDER_SIDE

• Aliases: - MVP_GENQ_SHMEM_POOL_FREE_QUEUE_SENDER_SIDE

  • MPICH_GENQ_SHMEM_POOL_FREE_QUEUE_SENDER_SIDE

• Description: - The genq shmem code allocates pools of cells on each

  • process and, when needed, a cell is removed from the pool and

  • passed to another process. This can happen by either removing a

  • cell from the pool of the sending process or from the pool of the

  • receiving process. This CVAR determines which pool to use. If true,

  • the cell will come from the sender-side. If false, the cell will

  • com from the receiver-side. There are specific advantages of using

  • receiver-side cells when combined with the “avx” fast configure

  • option, which allows MPICH to use AVX streaming copy

  • intrintrinsics, when available, to avoid polluting the cache of the

  • sender with the data being copied to the receiver. Using

  • receiver-side cells does have the trade-off of requiring an MPMC

  • lock for the free queue rather than an MPSC lock, which is used for

  • sender-side cells. Initial performance analysis shows that using

  • the MPMC lock in this case had no significant performance loss. By

  • default, the queue will continue to use sender-side queues until

  • the performance impact is verified.

• Default: 1

MPIR_CVAR_ENABLE_HCOLL

• Aliases: - MVP_ENABLE_HCOLL

  • MPICH_ENABLE_HCOLL

• Description: - Enable hcoll collective support.

• Default: 0

MPIR_CVAR_COLL_SCHED_DUMP

• Aliases: - MVP_COLL_SCHED_DUMP

  • MPICH_COLL_SCHED_DUMP

• Description: - Print schedule data for nonblocking collective operations.

• Default: 0

MPIR_CVAR_SHM_RANDOM_ADDR_RETRY

• Aliases: - MVP_SHM_RANDOM_ADDR_RETRY

  • MPICH_SHM_RANDOM_ADDR_RETRY

• Description: - The default number of retries for generating a random

  • address. A retrying involves only local operations.

• Default: 100

MPIR_CVAR_SHM_SYMHEAP_RETRY

• Aliases: - MVP_SHM_SYMHEAP_RETRY

  • MPICH_SHM_SYMHEAP_RETRY

• Description: - The default number of retries for allocating a symmetric

  • heap in shared memory. A retrying involves collective communication

  • over the group in the shared memory.

• Default: 100

MPIR_CVAR_ENABLE_HEAVY_YIELD

• Aliases: - MVP_ENABLE_HEAVY_YIELD

  • MPICH_ENABLE_HEAVY_YIELD

• Description: - If enabled, use nanosleep to ensure other threads have a

  • chance to grab the lock. Note: this may not work with some thread

  • runtimes, e.g. non-preemptive user-level threads.

• Default: 0