A comment to the below. I meant the 2x performance was for shared
memory communications.
--td
Message: 3
Date: Wed, 05 Aug 2009 09:55:42 -0400
From: Terry Dontje <terry.don...@sun.com>
Subject: Re: [OMPI users] Performance difference on OpenMPI, IntelMPI
and ScaliMPI
To: us...@open-mpi.org
Message-ID: <4a798f5e.3000...@sun.com>
Content-Type: text/plain; CHARSET=US-ASCII; format=flowed
We've found on certain applications binding to processors can have up to
a 2x difference. ScaliMPI automatically binds processes by socket so if
you are not running a one process per cpu job each process will land on
a different socket.
OMPI defaults to not binding at all. You may want to try and use the
rankfile option (see manpage) and see if that helps any.
If the above doesn't improve anything the next question is do you know
what the sizes of the messages are? For very small messages I believe
Scali shows a 2x better performance than Intel and OMPI (I think this is
due to a fastpath optimization).
