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Subject: Re: [OMPI users] OpenMPI flags conditions
From: Eugene Loh (eugene.loh_at_[hidden])
Date: 2010-07-15 14:27:47


Gabriele Fatigati wrote:

> Dear OpenMPI users,
>
> is it possible to define some set of parameters for a range number of
> processors and message size in openmpi-mca-params.conf ? For example:
>
> if nprocs<256
>
> some mca parameters...
>
> if nprocs > 256
>
> other mca parameters..
>
> and the same related to message size?

Message size? Depends on what you mean, but there are already
algorithms in OMPI that depend on message size and you can control those
dependences somewhat. E.g., you can set eager/rendezvous crossover
sizes. Apparently, you want something beyond what's already supported
today, but the point is that there are already some such controls in
there. Depending on how much more you want, this may be a topic beyond
just conf files. Perhaps what you're requesting requires altogether new
MCA parameters.