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Subject: Re: [OMPI devel] Revise paffinity method?
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-05-08 10:25:17


On May 8, 2009, at 6:35 AM, Terry Dontje wrote:

> So in essence the user might set one parameter and depending on
> whether
> orted is being used to launch the job or not determines when the
> process
> binding happens (process launch vs MPI_Init time). In the case that
> one
> needs/wants to rely on a different launcher to bind then you don't
> specify the OMPI parameter at all.
>
> Is that right?
>

Not really. The user still sets mpi_paffinity_alone. We just try to
handle it in the orted, and if that doesn't work (more specifically,
if there's no orted to do it), then we'll handle it in MPI_INIT.

There's a little extra secret sauce for the orted to tell the MPI
process "don't bother doing the paffinity, I did it for you
already" (that's the extra [internal] MCA param) so that MPI_INIT
knows not to do it.

> So, will there be a way to force MPI_Init based binding even if one is
> using orted to launch a job. Not sure there really is a use case for
> such just curious.
>

If anyone cares/has a use case, I'm sure this would not be hard to do.

-- 
Jeff Squyres
Cisco Systems