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Subject: Re: [OMPI users] errors trying to run a simple mpi task
From: dani (dani_at_[hidden])
Date: 2013-06-24 18:16:22


OK, I see the part I missed - changing the MTT parameters for mlx4_core.
My only issue is that currently there is no num_mtt or log_num_mtt, but there is log_mtts_per_seg in /sys/module/mlx4_core/parameters
Has the parameter names changed? I know I can simply set log_mtts_per_seg to 5 (it's currently 3) but the discussion at the mailing list (http://www.open-mpi.org/community/lists/devel/2012/08/11417.php) seems to indicate it's better to use numerous small chunks to avoid fragmentation.

Can you, or anyone else, provide documentation for the current parameters of mlx4_core? I can't locate it in the mellanox or ofed sites.


On 24/06//2013 18:02, Jeff Squyres (jsquyres) wrote:
On Jun 23, 2013, at 3:21 PM, dani <dani@letai.org.il> wrote:

See this Open MPI FAQ item for more information on these Linux kernel module
parameters:

    http://www.open-mpi.org/faq/?category=openfabrics#ib-locked-pages
BTW, the node has 64GB total ram. Is it possible openmpi is limited to only 32GB? or possibly the ofed installation has such a limit?
Yes.

See the FAQ item cited in the help message for more detail.