Bug#1102612: mpich 4.3 not initialising multiple processes

[Drew Parsons]

Package: mpich
Followup-For: Bug #1102612

Is this upstream bug related to the problem?
https://github.com/pmodels/mpich/issues/7064#issuecomment-2301026290

It suggests the pmix build configuration might be an issue.
The timing of that bug doesn't match well, though, it was made in
August 2024, before we had mpich 4.3.

On the other hand, pmix support was added to the debian mpich package
in 4.3.0-2. And Ubuntu 24.04 (the version in the upstream bug report)
has mpich 4.2.0-5build3, which did have pmix support activated.

Debian deactivated pmix support in mpich 4.2.0-5.1 (it had been
enabled in 4.2.0-1), evidently ubuntu didn't apply the update to
deactivate it.

There is more discussion from ubuntu at
https://bugs.launchpad.net/ubuntu/+source/mpich/+bug/2072338
though no actual fix for it, just a reference to the pmix deactivation
in 4.2.0-5.1

Sounds like pmix configuration is still an issue for mpich.