[torqueusers] IB epilogoue/prolog, and any other concerns

Chris Samuel csamuel at vpac.org
Fri May 30 01:19:46 MDT 2008

----- "Walid" <walid.shaari at gmail.com> wrote:

> Hi,

Hello Walid,

> My question is if you used any of the above and have any
> hints,gotches?

We started off with MVAPICH but moved to OpenMPI when we
found we had real problems getting any job larger than 64
CPUs to start with it.

OpenMPI also has *much* better error messages, and doesn't
have the dumb idea of enabling CPU affinity by default on
AMD64 systems (though that might be fixed by now).

Their code naively binds from cores 0->N, which is fine
until you run two 4 CPU codes on an 8 core node and why
they're running at half speed compared to just running
one job on its own.. :-(

Christopher Samuel - (03) 9925 4751 - Systems Manager
 The Victorian Partnership for Advanced Computing
 P.O. Box 201, Carlton South, VIC 3053, Australia
VPAC is a not-for-profit Registered Research Agency

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