[Beowulf] Performance degrading

Glen Beane Glen.Beane at jax.org
Tue Dec 15 12:10:47 PST 2009

On 12/15/09 2:36 PM, "Gus Correa" <gus at ldeo.columbia.edu> wrote:

If you have single quad core nodes as you said,
then top shows that you are oversubscribing the cores.
There are five nwchem processes are running.

It has been a very long time,  but wasn't that normal behavior for mpich under certain instances?  If I recall correctly it had an extra process that was required by the implementation. I don't think it returned from MPI_Init, so you'd have a bunch of processes consuming nearly a full CPU and then one that was mostly idle doing something behind the scenes.  I don't remember if this was for mpich/p4 (with or without -with-comm=shared) or for mpich-gm.

Glen L. Beane
Software Engineer
The Jackson Laboratory
Phone (207) 288-6153

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