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From: bmchapman_at_[hidden]
Date: 2005-07-18 11:48:30


Thanks to Edgar for copying me on this: it sounds like I asked at the right
time. There were some OpenMP-internal discussions on this a couple of years
ago, and a straw proposal, but at that time there was no obvious interest
on the MPI side. So we'd have to go back and look at the ideas that came up
at the time.
Barbara

> [Original Message]
> From: Jeff Squyres <jsquyres_at_[hidden]>
> To: Open MPI Developers <devel_at_[hidden]>
> Cc: Barbara Chapman <chapman_at_[hidden]>
> Date: 7/18/2005 10:44:15 AM
> Subject: Re: [O-MPI devel] processor affinity
>
> Excellent. Seems like several people have thought of this at the same
> time (I was pinged about this by the IB vendors).
>
> I know that others on the team have more experience in this area than I
> do, so I personally welcome all information. I've read a few papers on
> the topic (general/simplified consensus: memory and process affinity is
> good), but would appreciate any pointers to more material.
>
> After the theory, however, we need to decide on an implementation
> strategy. As Rich mentioned, we can do this all via MCA parameters, or
> perhaps via MPI_Info or MPI attributes. Although I'm not sure how much
> of this can be set ahead of time and what needs to be done on a
> per-thread basis, I'm assuming that each thread will need to make some
> kind of function call (if MPI is going to handle it, then it will need
> to be an MPI function call that triggers some magic under the covers).
>
> Any advice here from the Open MP community would also be appreciated...
>
>
> On Jul 18, 2005, at 11:08 AM, Edgar Gabriel wrote:
>
> > We have currently Barbara Chapman from the University of Houston as a
> > guest scientist here at Stuttgart. Most of you might now, that Barbara
> > is working on compiler design and OpenMP issues. This afternoon she
> > dropped in my office and asked me, whether the Open MPI group has
> > thought/discussed processor affinity issues up to now (which we just
> > did
> > :-) ).
> >
> > Anyway, I just wanted to point out, that various people from the OpenMP
> > community have been working/are still working on this issue, and that
> > it
> > might be interesting to exchange information and maybe coordinate the
> > approaches. I cc'ed Barbara therefore also on this email...
>
> --
> {+} Jeff Squyres
> {+} The Open MPI Project
> {+} http://www.open-mpi.org/