在c++/mpi(mvapich)中有一个简单的程序，发送一个float类型的数组。当我使用 MPI_Send、MPI_Ssend、MPI_Rsend 时，如果数据的大小超过急切阈值(在我的程序中为 64k)，则在调用 MPI_Send 期间我的程序挂起。如果数组小于阈值，程序运行正常。源代码如下:
#include "mpi.h"
#include <unistd.h>
#include <stdio.h>
int main(int argc,char *argv[]) {
int mype=0,size=1;
MPI_Init(&argc,&argv);
MPI_Comm_rank(MPI_COMM_WORLD,&mype);
MPI_Comm_size(MPI_COMM_WORLD,&size);
int num = 2048*2048;
float* h_pos = new float[num];
MPI_Status stat;
if(mype == 0)
{
MPI_Rsend(h_pos, 20000, MPI_FLOAT, 1, 5, MPI_COMM_WORLD);
}
if(mype == 1)
{
printf("%fkb\n", 20000.0f*sizeof(float)/1024);
MPI_Recv(h_pos, 20000, MPI_FLOAT, 0, 5, MPI_COMM_WORLD, &stat);
}
MPI_Finalize();
return 0;
}
我想我的设置可能有误，参数如下:
MVAPICH2 All Parameters
MV2_COMM_WORLD_LOCAL_RANK : 0
PMI_ID : 0
MPIRUN_RSH_LAUNCH : 0
MPISPAWN_GLOBAL_NPROCS : 2
MPISPAWN_MPIRUN_HOST : g718a
MPISPAWN_MPIRUN_ID : 10800
MPISPAWN_NNODES : 1
MPISPAWN_WORKING_DIR : /home/g718a/new_workspace/mpi_test
USE_LINEAR_SSH : 1
PMI_PORT : g718a:42714
MV2_3DTORUS_SUPPORT : 0
MV2_NUM_SA_QUERY_RETRIES : 20
MV2_NUM_SLS : 8
MV2_DEFAULT_SERVICE_LEVEL : 0
MV2_PATH_SL_QUERY : 0
MV2_USE_QOS : 0
MV2_ALLGATHER_BRUCK_THRESHOLD : 524288
MV2_ALLGATHER_RD_THRESHOLD : 81920
MV2_ALLGATHER_REVERSE_RANKING : 1
MV2_ALLGATHERV_RD_THRESHOLD : 0
MV2_ALLREDUCE_2LEVEL_MSG : 262144
MV2_ALLREDUCE_SHORT_MSG : 2048
MV2_ALLTOALL_MEDIUM_MSG : 16384
MV2_ALLTOALL_SMALL_MSG : 2048
MV2_ALLTOALL_THROTTLE_FACTOR : 4
MV2_BCAST_TWO_LEVEL_SYSTEM_SIZE : 64
MV2_GATHER_SWITCH_PT : 0
MV2_INTRA_SHMEM_REDUCE_MSG : 2048
MV2_KNOMIAL_2LEVEL_BCAST_MESSAGE_SIZE_THRESHOLD : 2048
MV2_KNOMIAL_2LEVEL_BCAST_SYSTEM_SIZE_THRESHOLD : 64
MV2_KNOMIAL_INTER_LEADER_THRESHOLD : 65536
MV2_KNOMIAL_INTER_NODE_FACTOR : 4
MV2_KNOMIAL_INTRA_NODE_FACTOR : 4
MV2_KNOMIAL_INTRA_NODE_THRESHOLD : 131072
MV2_RED_SCAT_LARGE_MSG : 524288
MV2_RED_SCAT_SHORT_MSG : 64
MV2_REDUCE_2LEVEL_MSG : 16384
MV2_REDUCE_SHORT_MSG : 8192
MV2_SCATTER_MEDIUM_MSG : 0
MV2_SCATTER_SMALL_MSG : 0
MV2_SHMEM_ALLREDUCE_MSG : 32768
MV2_SHMEM_COLL_MAX_MSG_SIZE : 131072
MV2_SHMEM_COLL_NUM_COMM : 8
MV2_SHMEM_COLL_NUM_PROCS : 2
MV2_SHMEM_COLL_SPIN_COUNT : 5
MV2_SHMEM_REDUCE_MSG : 4096
MV2_USE_BCAST_SHORT_MSG : 16384
MV2_USE_DIRECT_GATHER : 1
MV2_USE_DIRECT_GATHER_SYSTEM_SIZE_MEDIUM : 1024
MV2_USE_DIRECT_GATHER_SYSTEM_SIZE_SMALL : 384
MV2_USE_DIRECT_SCATTER : 1
MV2_USE_OSU_COLLECTIVES : 1
MV2_USE_OSU_NB_COLLECTIVES : 1
MV2_USE_KNOMIAL_2LEVEL_BCAST : 1
MV2_USE_KNOMIAL_INTER_LEADER_BCAST : 1
MV2_USE_SCATTER_RD_INTER_LEADER_BCAST : 1
MV2_USE_SCATTER_RING_INTER_LEADER_BCAST : 1
MV2_USE_SHMEM_ALLREDUCE : 1
MV2_USE_SHMEM_BARRIER : 1
MV2_USE_SHMEM_BCAST : 1
MV2_USE_SHMEM_COLL : 1
MV2_USE_SHMEM_REDUCE : 1
MV2_USE_TWO_LEVEL_GATHER : 1
MV2_USE_TWO_LEVEL_SCATTER : 1
MV2_USE_XOR_ALLTOALL : 1
MV2_DEFAULT_SRC_PATH_BITS : 0
MV2_DEFAULT_STATIC_RATE : 0
MV2_DEFAULT_TIME_OUT : 67374100
MV2_DEFAULT_MTU : 0
MV2_DEFAULT_PKEY : 0
MV2_DEFAULT_PORT : -1
MV2_DEFAULT_GID_INDEX : 0
MV2_DEFAULT_PSN : 0
MV2_DEFAULT_MAX_RECV_WQE : 128
MV2_DEFAULT_MAX_SEND_WQE : 64
MV2_DEFAULT_MAX_SG_LIST : 1
MV2_DEFAULT_MIN_RNR_TIMER : 12
MV2_DEFAULT_QP_OUS_RD_ATOM : 257
MV2_DEFAULT_RETRY_COUNT : 67900423
MV2_DEFAULT_RNR_RETRY : 202639111
MV2_DEFAULT_MAX_CQ_SIZE : 40000
MV2_DEFAULT_MAX_RDMA_DST_OPS : 4
MV2_INITIAL_PREPOST_DEPTH : 10
MV2_IWARP_MULTIPLE_CQ_THRESHOLD : 32
MV2_NUM_HCAS : 1
MV2_NUM_NODES_IN_JOB : 1
MV2_NUM_PORTS : 1
MV2_NUM_QP_PER_PORT : 1
MV2_MAX_RDMA_CONNECT_ATTEMPTS : 10
MV2_ON_DEMAND_UD_INFO_EXCHANGE : 1
MV2_PREPOST_DEPTH : 64
MV2_HOMOGENEOUS_CLUSTER : 0
MV2_COALESCE_THRESHOLD : 6
MV2_DREG_CACHE_LIMIT : 0
MV2_IBA_EAGER_THRESHOLD : 0
MV2_MAX_INLINE_SIZE : 0
MV2_MAX_R3_PENDING_DATA : 524288
MV2_MED_MSG_RAIL_SHARING_POLICY : 0
MV2_NDREG_ENTRIES : 0
MV2_NUM_RDMA_BUFFER : 0
MV2_NUM_SPINS_BEFORE_LOCK : 2000
MV2_POLLING_LEVEL : 1
MV2_POLLING_SET_LIMIT : -1
MV2_POLLING_SET_THRESHOLD : 256
MV2_R3_NOCACHE_THRESHOLD : 32768
MV2_R3_THRESHOLD : 4096
MV2_RAIL_SHARING_LARGE_MSG_THRESHOLD : 16384
MV2_RAIL_SHARING_MED_MSG_THRESHOLD : 2048
MV2_RAIL_SHARING_POLICY : 4
MV2_RDMA_EAGER_LIMIT : 32
MV2_RDMA_FAST_PATH_BUF_SIZE : 4096
MV2_RDMA_NUM_EXTRA_POLLS : 1
MV2_RNDV_EXT_SENDQ_SIZE : 5
MV2_RNDV_PROTOCOL : 3
MV2_SMALL_MSG_RAIL_SHARING_POLICY : 0
MV2_SPIN_COUNT : 5000
MV2_SRQ_LIMIT : 30
MV2_SRQ_MAX_SIZE : 4096
MV2_SRQ_SIZE : 256
MV2_STRIPING_THRESHOLD : 8192
MV2_USE_COALESCE : 0
MV2_USE_XRC : 0
MV2_VBUF_MAX : -1
MV2_VBUF_POOL_SIZE : 512
MV2_VBUF_SECONDARY_POOL_SIZE : 256
MV2_VBUF_TOTAL_SIZE : 0
MV2_USE_HWLOC_CPU_BINDING : 1
MV2_ENABLE_AFFINITY : 1
MV2_ENABLE_LEASTLOAD : 0
MV2_SMP_BATCH_SIZE : 8
MV2_SMP_EAGERSIZE : 65537
MV2_SMPI_LENGTH_QUEUE : 262144
MV2_SMP_NUM_SEND_BUFFER : 256
MV2_SMP_SEND_BUF_SIZE : 131072
MV2_USE_SHARED_MEM : 1
MV2_CUDA_BLOCK_SIZE : 0
MV2_CUDA_NUM_RNDV_BLOCKS : 8
MV2_CUDA_VECTOR_OPT : 1
MV2_CUDA_KERNEL_OPT : 1
MV2_EAGER_CUDAHOST_REG : 0
MV2_USE_CUDA : 1
MV2_CUDA_NUM_EVENTS : 64
MV2_CUDA_IPC : 1
MV2_CUDA_IPC_THRESHOLD : 0
MV2_CUDA_ENABLE_IPC_CACHE : 0
MV2_CUDA_IPC_MAX_CACHE_ENTRIES : 1
MV2_CUDA_IPC_NUM_STAGE_BUFFERS : 2
MV2_CUDA_IPC_STAGE_BUF_SIZE : 524288
MV2_CUDA_IPC_BUFFERED : 1
MV2_CUDA_IPC_BUFFERED_LIMIT : 33554432
MV2_CUDA_IPC_SYNC_LIMIT : 16384
MV2_CUDA_USE_NAIVE : 1
MV2_CUDA_REGISTER_NAIVE_BUF : 524288
MV2_CUDA_GATHER_NAIVE_LIMIT : 32768
MV2_CUDA_SCATTER_NAIVE_LIMIT : 2048
MV2_CUDA_ALLGATHER_NAIVE_LIMIT : 1048576
MV2_CUDA_ALLGATHERV_NAIVE_LIMIT : 524288
MV2_CUDA_ALLTOALL_NAIVE_LIMIT : 262144
MV2_CUDA_ALLTOALLV_NAIVE_LIMIT : 262144
MV2_CUDA_BCAST_NAIVE_LIMIT : 2097152
MV2_CUDA_GATHERV_NAIVE_LIMIT : 0
MV2_CUDA_SCATTERV_NAIVE_LIMIT : 16384
MV2_CUDA_ALLTOALL_DYNAMIC : 1
MV2_CUDA_ALLGATHER_RD_LIMIT : 1024
MV2_CUDA_ALLGATHER_FGP : 1
MV2_SMP_CUDA_PIPELINE : 1
MV2_CUDA_INIT_CONTEXT : 1
MV2_SHOW_ENV_INFO : 2
MV2_DEFAULT_PUT_GET_LIST_SIZE : 200
MV2_EAGERSIZE_1SC : 0
MV2_GET_FALLBACK_THRESHOLD : 0
MV2_PIN_POOL_SIZE : 2097152
MV2_PUT_FALLBACK_THRESHOLD : 0
MV2_ASYNC_THREAD_STACK_SIZE : 1048576
MV2_THREAD_YIELD_SPIN_THRESHOLD : 5
MV2_USE_HUGEPAGES : 1
和配置:
mpiname -a
MVAPICH2 2.0 Fri Jun 20 20:00:00 EDT 2014 ch3:mrail
Compilation
CC: gcc -DNDEBUG -DNVALGRIND -O2
CXX: g++ -DNDEBUG -DNVALGRIND
F77: no -L/lib -L/lib
FC: no
Configuration
-with-device=ch3:mrail --with-rdma=gen2 --enable-cuda --disable-f77 --disable-fc --disable-mcast
程序运行在 2 个进程上:
mpirun_rsh -hostfile hosts -n 2 MV2_USE_CUDA=1 MV2_SHOW_ENV_INFO=2 ./myTest
有什么想法吗？
最佳答案
A send that uses the ready communication mode may be started only if the matching receive is already posted. Otherwise, the operation is erroneous and its outcome is undefined.
在这个程序中，不保证 Recv 会在 Rsend 之前发送，因此操作可能会失败或挂起。
关于c++ - MVAPICH 在 MPI_Send 上挂起大于急切阈值的消息，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27405813/