Since we have successfully created a cluster of Raspberry Pis, we now need to test their performance. One way of doing that is to measure the latency between different nodes. To this end, Ohio State University has created some benchmarking tests that are included with the mpi4py library. We will run a few of these to measure the performance of our cluster. Simply put, latency measures the amount of time a packet takes to reach its destination and get a response. The lower the latency, the better a cluster will perform. The tests are given in the demo folder of the mpi4py directory. These run in this fashion: the osu_bcast benchmark measures the latency of the MPI_Bcast collective operation across N processes. It measures the minimum, maximum, and average latency for various message lengths and over a large number of iterations.
To run the osu_allgather.py test, we execute the following command:
mpiexec -f machinefile -n 3 python osu_allgather.py
As...