Re: benchmarking on Cray XT4

From: Axel Kohlmeyer (
Date: Tue Mar 16 2010 - 06:49:58 CDT

what NAMD binary are you using?
a downloaded one? a self-compiled one?


On Tue, Mar 16, 2010 at 5:50 AM, Hannes Loeffler
<> wrote:
> Hi,
> I am currently running some benchmarks on a Cray XT4 with quad-core
> processors.  Users can choose how many tasks to run per processor.
> What I find is that a single task/processor outperforms a two
> task/processor run which itself is faster than a four task/processor
> run.  I see this behaviour for processor counts from 8 to 2048.  Now,
> I do understand that there may be performance hits when certain
> resource are shared but I would still have expected a different
> outcome.  Can anyone comment on my findings?  Is that the
> performance that I have to expect from namd on this architecture?
> Cheers,
> Hannes.

Dr. Axel Kohlmeyer
Institute for Computational Molecular Science
Temple University, Philadelphia PA, USA.

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