Skyld MPI implementation, how to choose nodes?

[Heiko Carstens]

Hi!

A couple of days ago, we installed a cluster of Athlon machines using the
fabulous preview of Skyld beowulf. Everything went fine, the demo apps run
smoothly and we altered our own software for molecular dynamics
simulations to use the Skyld implementation of MPI.

Now as we understand, there is no way with mpirun from Skyld to choose a
group of nodes for a job, as one can do with the 'machinefile' option for
MPICH-mpirun. It even happens that if one starts up multiple jobs, which
each use only a small number of nodes, all these jobs end up on the _same_
nodes, while others are idle!

Has someone figured out how to do it? We read all of the documentation and
are stuck now, as the source code for MPI seems to be unavailable.

Furthermore this makes the introduction of a queuing system impossible, as
one has to devide the nodes into groups.

Any help is greatly appreciated.

Cheers,
Heiko

--
Heiko Carstens                          carstens at imo.physik.uni-muenchen.de
University of Munich
Chair for BioMolecular Optics