Filter
Top Products
A – Benchmark Programs
Benchmark 4: Measuring MPI Latency in Host Rings
IB6054601-00 D A-5
Q
A.4
Benchmark 4: Measuring MPI Latency in Host Rings
The program mpi_latency can be used to measure latency in a ring of hosts. Its
syntax is a bit different from Benchmark 1 in that it takes command line arguments
that let you specify the message size and the number of messages over which to
average the results. So, for example, if you have a hosts file listing four or more
nodes, the command:
$ mpirun -np 4 -ppn 1 -m mpihosts mpi_latency 100 0
might produce output like this:
0 1.760125
This indicates that it took an average of 1.76 microseconds per hop to send a
zero-length message from the first host, to the second, to the third, to the fourth,
and then get replies back in the other direction.