MPICH support
We currently do not have support for MPICH, making site/vendor replacement of MPI impossible unless the site/vendor supports OpenMPI.
Both OpenMPI and MPICH rely on libfabric
and UCX
to provide support for interconnects. Unfortunately, while OpenMPI can be built "fat" (supporting both UCX
and libfabric
within one installation), for MPICH we need to chose between them. This makes including MPICH in EESSI a little tricky. One option is to go ahead and build MPICH twice in ucx
and libfabric
subdirectories of the installation folder, then use a parameter in the easyconfig to decide which one becomes the default (and get's added to the module file). In EESSI, we would then just need to decide what our default should be (most likely libfabric
) and if a site needs something else they can use our MPI ABI override capabilities to select the other build.