UsingMultipleMPIs

Proposal for Improving MPI support in Fedora

Written by EdHill.

Observation

People are increasingly using MPI to solve scientific and engineering problems. While its still a niche market, its steadily growing. Networks of workstations and small clusters have become quite common. And cheaper computers is only making it more common.

Goal

It would be nice to provide a few different MPI implementations which can be installed with a single command

yum install mpich2 openmpi ...

and then operate them side-by-side without worries about conflicts. In my opinion, there are no good reasons why Fedora users should be "stuck" with LAM and forced to fight with from-source builds for other MPI implementations. We easily can and therefore should do better!

Proposal

On a large number sites (ranging from "supercomputing centres" right through through medium and small cluster installs), admins have adopted the "modules" or environment-modules software to easily and gracefully handle situations with multiple simultaneous installs of various compilers and/or libraries. The environment-modules system has proven itself to be a solid, general, workable, and extensible framework. While I don't suggest that Fedora (or even Fedora Extras) adopt environment-modules wholesale for all sorts of problems, the simultaneous installation of multiple MPI implementations is a situation that just begs for an environment-modules solution.

The alternatives approach suggested by others is, in my opinion, clearly inferior to environment-modules since:

• where does one put the man pages for each implementation?
• the alternatives setup is NOT easily extended to multiple different compilers
• alternatives has the concept of one implementation being preferred to all others and this is unnecessary/pointless in the context of multiple MPI implementations

With the recent addition of environment-modules to Fedora Extras, I'd like to see it used to solve the current multiple-MPI-implementations deadlock.

Comments

There is a new implementation of environment modules called Lmod[[1]] or "Lua based modules", this project is getting a lot of traction in the supercomputing community. With documentation too![[2]] -j0hn