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Running MPI jobs

Launching MPI jobs in OpenMPI

To execute message passing parallel jobs these should be built against one of the MPI libraries provided by the support team as a module. To execute an MPI job for an executable build with an OpenMPI library, your job script should do the following:

  • Load the compiler module you have been using
  • Load the OpenMPI module relevant to the compiler you are using
  • Start the program with mpirun
  • Using the correct binding can help code performance.
    • When using 20 tasks per node on Aurora, we recommend using the -bind-to core option of mpirun
    • When using fewer than 16 tasks we recommend experimenting with whether not using binding helps or hinders performance.

Launching MPI jobs compiled with the Intel MPI library

When the Intel MPI library was used to build your executable, your jobsscript should do as follows:

  • Load the compiler module you have been using
  • Load the Intel MPI module relevant to your compiler
  • Start your program with srun

When using LUNARC provided software, and you are loading an impi module to see your package, you need to use srun to start MPI executables of this package.

Info

Task binding for the Intel MPI library is still under investigation

Author: (LUNARC)

Last Updated: 2022-10-05