Uppsala Multidisciplinary Center for Advanced Computational Science

Poor performance using Intel MPI on Rackham


We have idenfied performance issues when using Intel MPI on Rackham. In some cases you see a 10x slowdown (or worse) using Intel MPI compared to Open MPI. We are investigating this issue and hope to have it solved soon. For now, please use Open MPI.

Note that the issues seems to occur regardless of compiler (gcc vs icc). Using icc + Open MPI appears to work.