Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] Factor of 10 loss in performance with 1.3.x
From: Steve Kargl (sgk_at_[hidden])
Date: 2009-04-07 12:25:36

On Tue, Apr 07, 2009 at 08:00:39AM -0700, Eugene Loh wrote:
> Iain Bason wrote:
> >There are a bunch changes in the shared memory module between 1.2.9
> >and 1.3.1. One significant change is the introduction of the "sendi"
> >internal interface. I believe George Bosilca did the initial
> >implementation. This is just a wild guess, but maybe there is
> >something about sendi that increases latency when using the shared
> >memory module.
> But the sm BTL doesn't expose its sendi function, which puts it in the
> same camp as most BTLs.
> And the slowdown doesn't seem to be observed by anyone other than Steve
> and his colleague?

Is there a debug option that I can try?

I've re-installed 1.3.1 several times yesterday using
various combination of configure options. There was no
change in observed performance.

I've tried --disable-smp-locks.
I've tried --enable-mpi-threads --with-threads=posix.
I've tried --enable-ptmalloc2-internal.

I'm willing to try whatever is required to debug this issue.