I've been trying to use OpenMPI with OpenMP and when I run try to run 2 MPI processes and 4 threads on one machine, all threads are executed on the same core at 25% usage instead of on 4 separate cores. I was able to fix this using --enable-mpi-threads when building OpenMPI; but now I am having an issue with this being a duel CPU machine.
There are 8 cores per processor, 2 processors in each server. If I run 2 MPI processes and 8 threads then everything is fine as long as the 2 processes started on separate processors, but if I try and do 1 MPI process with 16 threads it reverts to stacking every thread on one core.
Has anyone had any experience running OpenMPI and OpenMP together?