No expert on this but the output file states wether peer-to-peer
communication is on or off.
Best,
Andy
On 04/04/2017 04:43 AM, Chris Neale wrote:
> Dear AMBER users:
>
> I have a system with ~ 200,000 atoms that scales quite well on 4 GPUs on a
> DGX machine with Amber16. I now have access to a different node for testing
> purposes that has 3 Tesla P100 GPUs. I find that 1 GPU gives 21 ns/day, 2
> GPUs give 31 ns/day and 3 GPUs give 21 ns/day. Strange thing is that 2 GPUs
> gives a consistent speed when I use GPUs 0,1 or 1,2 or 0,2 -- leading me to
> think that there is PCI-based peer-to-peer across all 3 GPUs (though I
> don't know how to verify that). So then why does performance drop off with
> 3 GPUs? I don't currently have the ability to re-test with 3 GPUs on a DGX,
> though I will look into testing that, since it could give a definitve
> answer.
>
> I'm wondering whether there is something obviously inherent to the code
> that doesn't like 3 GPUs (vs. 2 or 4)? Any thoughts?
>
> Thank you for your help,
> Chris.
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--
M.Sc. Andreas Tosstorff
Lehrstuhl für Pharmazeutische Technologie und Biopharmazie
Department Pharmazie
LMU München
Butenandtstr. 5-13 ( Haus B)
81377 München
Germany
Tel.: +49 89 2180 77059
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Received on Tue Apr 04 2017 - 00:30:02 PDT
