Advanced MPI scheduling
This is not a complete article: This is a draft, a work in progress that is intended to be published into an article, which may or may not be ready for inclusion in the main wiki. It should not necessarily be considered factual or authoritative.
Most users should submit MPI or distributed memory parallel jobs following the example
given at Running jobs. Simply request a number of
processes with --ntasks or -n and trust the scheduler
to allocate those processes in a way that balances the efficiency of your job
with the overall efficiency of the cluster.
If you want more control over how your job is allocated, then SchedMD's
page on multicore support is a good
place to begin. It describes how many of the options to the
sbatch
command interact to constrain the placement of processes.
You may find this discussion of What exactly is considered a CPU? in SLURM to be useful.
Hybrid jobs: MPI and OpenMP, or MPI and threads[edit]
To come
MPI and GPUs[edit]
To come
Troubleshooting and performance monitoring[edit]
To come
Why srun instead of mpiexec or mpirun?[edit]
To come