Communications speed in MPIch



The following test program is part of the MPIch standard distribution.

Communications are exchanged between two nodes (node00 and node01 here).

Expected hardware peak rate is 12.5 Mbytes/sec.


node00:/home/hamberh/mpi/test> ./mpirun -np 2 ./systest


Process 0 is alive on

Process 1 is alive on


Options: 0=quit, 1=Hello, 2=Ring : 2


Ring test...time network performance



Input maximum message size: 1000000

len=1 bytes, used= 0.034863 sec., rate=0.000057 Mbytes/sec

len=2 bytes, used= 0.000329 sec., rate=0.012158 Mbytes/sec

len=4 bytes, used= 0.000325 sec., rate=0.024615 Mbytes/sec

len=8 bytes, used= 0.000327 sec., rate=0.048930 Mbytes/sec

len=16 bytes, used= 0.000328 sec., rate=0.097561 Mbytes/sec

len=32 bytes, used= 0.000328 sec., rate=0.195122 Mbytes/sec

len=64 bytes, used= 0.000333 sec., rate=0.384384 Mbytes/sec

len=128 bytes, used= 0.000346 sec., rate=0.739884 Mbytes/sec

len=256 bytes, used= 0.000366 sec., rate=1.398907 Mbytes/sec

len=512 bytes, used= 0.000458 sec., rate=2.235808 Mbytes/sec

len=1024 bytes, used= 0.000672 sec., rate=3.047619 Mbytes/sec

len=2048 bytes, used= 0.000946 sec., rate=4.329810 Mbytes/sec

len=4096 bytes, used= 0.001415 sec., rate=5.789399 Mbytes/sec

len=8192 bytes, used= 0.011025 sec., rate=1.486077 Mbytes/sec

len=16384 bytes, used= 0.019719 sec., rate=1.661748 Mbytes/sec

len=32768 bytes, used= 0.039988 sec., rate=1.638892 Mbytes/sec

len=65536 bytes, used= 0.020107 sec., rate=6.518725 Mbytes/sec

len=131072 bytes, used= 0.040206 sec., rate=6.520022 Mbytes/sec

len=262144 bytes, used= 0.052425 sec., rate=10.000725 Mbytes/sec

len=524288 bytes, used= 0.131467 sec., rate=7.975964 Mbytes/sec

clock resolution in seconds: 0.00000600