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Subject: Re: [OMPI users] Question on handling of memory for communications
From: Jeff Squyres (jsquyres) (jsquyres_at_[hidden])
Date: 2013-07-08 14:07:06

On Jul 8, 2013, at 2:01 PM, Brice Goglin <Brice.Goglin_at_[hidden]> wrote:

> The driver doesn't allocate much memory here. Maybe some small control buffers, but nothing significantly involved in large message transfer performance. Everything critical here is allocated by user-space (either MPI lib or application), so we just have to make sure we bind the process memory properly. I used hwloc-bind to do that.


Remember that the point of IB and other operating-system bypass devices is that the driver is not involved in the fast path of sending / receiving. One of the side-effects of that design point is that userspace does all the allocation of send / receive buffers.

Jeff Squyres
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