ANNOUNCEMENT: mpiexec mailing list and mpich/p4 support

Pete Wyckoff pw at
Wed Jan 9 12:56:18 PST 2002

Mpiexec is a replacement program for the standard "mpirun" script that
people have traditionally used to start parallel jobs.  Mpiexec is used
specifically to initialize a parallel job from within a PBS batch or
interactive environment.

Mpiexec uses the task manager library of PBS to spawn copies of the
executable on the nodes in a PBS allocation.  This is much faster than
invoking a separate rsh once for each process.  Another benefit is that
resources used by the spawned processes are accounted correctly with
mpiexec, and reported in the PBS logs.  Plus there's lots of knobs you
can twist to control job placement, input and output stream handling,
and other variations.

The distribution, including instructions for CVS access, can be found

We've recently created a mailing list for mpiexec, mpiexec at
You can subscribe using the standard mailman techniques; see

for information and archives.

The latest news is addition of support for those who use ethernet for
message passing, using MPICH with its P4 library.  The other MPI
libraries supported are MPICH/GM (Myrinet) and EMP (research gigabit
ethernet).  I'd love to support LAM as well, but could use some help
with that.  Mpiexec is developed on a linux/ia64 environment, but
there's no reason it shouldn't work on clusters using other POSIX-like
operating systems.  Patches to support other systems will be happily

To use mpiexec in your cluster, you'll need to be willing to apply a
small patch to your PBS distribution to use all the functionality of
mpiexec.  If you use MPICH/P4, you'll need to apply a rather large patch
to MPICH, although the MPICH developers are working to apply much of it
to their official distribution.

		-- Pete

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