Time MPI通信延迟-消息的大小是否重要?
我一直在研究并行算法中的时间测量(基准测试),更具体地说,是矩阵乘法。我使用以下算法:Time MPI通信延迟-消息的大小是否重要?,time,matrix,benchmarking,delay,mpi,Time,Matrix,Benchmarking,Delay,Mpi,我一直在研究并行算法中的时间测量(基准测试),更具体地说,是矩阵乘法。我使用以下算法: if(taskid==MASTER) { averow = NRA/numworkers; extra = NRA%numworkers; offset = 0; mtype = FROM_MASTER; for (dest=1; dest<=numworkers; dest++) { rows = (dest <= extra) ? averow+1 : ave
if(taskid==MASTER) {
averow = NRA/numworkers;
extra = NRA%numworkers;
offset = 0;
mtype = FROM_MASTER;
for (dest=1; dest<=numworkers; dest++)
{
rows = (dest <= extra) ? averow+1 : averow;
MPI_Send(&offset, 1, MPI_INT, dest, mtype, MPI_COMM_WORLD);
MPI_Send(&rows, 1, MPI_INT, dest, mtype, MPI_COMM_WORLD);
MPI_Send(&a[offset][0], rows*NCA, MPI_DOUBLE, dest, mtype,MPI_COMM_WORLD);
MPI_Send(&b, NCA*NCB, MPI_DOUBLE, dest, mtype, MPI_COMM_WORLD);
offset = offset + rows;
}
mtype = FROM_WORKER;
for (i=1; i<=numworkers; i++)
{
source = i;
MPI_Recv(&offset, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status);
MPI_Recv(&rows, 1, MPI_INT, source, mtype, MPI_COMM_WORLD, &status);
MPI_Recv(&c[offset][0], rows*NCB, MPI_DOUBLE, source, mtype,
MPI_COMM_WORLD, &status);
printf("Resultados recebidos do processo %d\n",source);
}
}
else {
mtype = FROM_MASTER;
MPI_Recv(&offset, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &status);
MPI_Recv(&rows, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD, &status);
MPI_Recv(&a, rows*NCA, MPI_DOUBLE, MASTER, mtype, MPI_COMM_WORLD, &status);
MPI_Recv(&b, NCA*NCB, MPI_DOUBLE, MASTER, mtype, MPI_COMM_WORLD, &status);
for (k=0; k<NCB; k++)
for (i=0; i<rows; i++)
{
c[i][k] = 0.0;
for (j=0; j<NCA; j++)
c[i][k] = c[i][k] + a[i][j] * b[j][k];
}
mtype = FROM_WORKER;
MPI_Send(&offset, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD);
MPI_Send(&rows, 1, MPI_INT, MASTER, mtype, MPI_COMM_WORLD);
MPI_Send(&c, rows*NCB, MPI_DOUBLE, MASTER, mtype, MPI_COMM_WORLD);
}
if(taskid==MASTER){
averow=NRA/numworkers;
额外=NRA%的工人;
偏移量=0;
mtype=来自主控;
对于(dest=1;dest,通过MPI发送的消息的大小肯定会影响性能
查看一个流行的MPI中发布的图表
实现的网页
正如您在第一张图中所看到的,通信延迟会增加
这一趋势适用于任何网络,而不仅仅是InfiniBand
如图所示。通过MPI发送的消息的大小肯定会影响性能
查看一个流行的MPI中发布的图表
实现的网页
正如您在第一张图中所看到的,通信延迟会增加
这一趋势适用于任何网络,而不仅仅是InfiniBand
如图所示