Merge pull request #16839 from gbtitus/comm-ofi-pmix-wo-module
Improve PMI out-of-band selection on CS and similar systems.
(Co-developed and reviewed by @ronawho.)
On systems with a Slurm that supports the PMIx server side interface,
and a pmix module for the client-side library, we’ve been able to use
the PMI2-based comm=ofi out-of-band support with PMIx for quite a while.
But wider experience with the CS systems where we first encountered this
configuration indicates there may be other options: Slurm itself may
supply both the client- and server-side PMI2 support. Or, there may be
a PMIx client-side library available even if there is no module for it.
Here, adjust the testing setup script for comm=ofi to take advantage of
both of those cases, and adjust the ordering so that we check for Slurm
supplying PMI2 first, then PMIx with or without a module.