Re: Running NAMD on Intel OmniPath

From: David Hardy (dhardy_at_ks.uiuc.edu)
Date: Thu Jul 27 2017 - 16:36:47 CDT

Hi Giacomo,

For Inifiniband, you do want verbs or ibverbs rather than MPI.

However, Omnipath is supposedly incompatible with ibverbs. The release notes say that you can build verbs for Omnipath using --with-qlogic, but Jim and the Charm++ developers tell me that MPI with SMP gives better performance.

Best regards,
Dave

> On Jul 27, 2017, at 2:33 PM, Giacomo Fiorin <giacomo.fiorin_at_gmail.com> wrote:
>
> Hi David, can you clarify the following from the release notes?
>
> MPI-based SMP builds have worse performance than verbs or ibverbs and
> are not recommended, particularly for GPU-accelerated builds.
>
> I don't have an OmniPath machine accessible to test whether this is true, but it is possibly a concern.
>
> Giacomo‚Äč

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