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From: David Burns (3db14_at_[hidden])
Date: 2007-03-21 17:29:13

I have used POSIX threading and Open MPI without problems on our Opteron
2216 Cluster (4 cores per node). Moving to core-level parallelization
with multi threading resulted in significant performance gains.

Sam Adams wrote:
> I have been looking, but I haven't really found a good answer about
> system level threading. We are about to get a new cluster of
> dual-processor quad-core nodes or 8 cores per node. Traditionally I
> would just tell MPI to launch two processes per dual processor single
> core node, but with eight cores on a node, having 8 processes seems
> inefficient.
> My question is this: does OpenMPI sense that there are multiple cores
> on a node and use something like pthreads instead of creating new
> processes automatically when I request 8 processes for a node, or
> should I run a single process per node and use OpenMP or pthreads
> explicitly to get better performance on a per node basis?