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Subject: Re: [OMPI users] MPI_THREAD_FUNNELED and enable-mpi-thread-multiple
From: Roland Schulz (roland_at_[hidden])
Date: 2013-02-05 00:09:09


On Mon, Jan 28, 2013 at 9:20 PM, Brian Budge <brian.budge_at_[hidden]> wrote:

> I believe that yes, you have to compile enable-mpi-thread-multiple to
> get anything other than SINGLE.
>

I just tested that compiling with enable-opal-multi-threads also makes
MPI_Init_thread return MPI_THREAD_FUNNELED.
Does enable-opal-multi-threads have any performance impact? According to
http://www.open-mpi.org/community/lists/users/2012/10/20587.phpenable-mpi-thread-multiple
has significant performance impact (at least for
IB). But I couldn't find any description of whether this is also true for
enable-opal-multi-threads.

Also why is enable-opal-multi-threads required for MPI_THREAD_FUNNELED? This
was asked before (e.g.
http://www.open-mpi.org/community/lists/devel/2010/05/7900.php) but I
couldn't find any answer. What does the option change? The README
states: "Enables
thread lock support in the OPAL and ORTE layers.", but that is not very
useful for a user. Also why is it not enabled by default?

Roland

>
> Brian
>
> On Tue, Jan 22, 2013 at 12:56 PM, Roland Schulz <roland_at_[hidden]> wrote:
> > Hi,
> >
> > compiling 1.6.1 or 1.6.2 without enable-mpi-thread-multiple returns from
> > MPI_Init_thread as provided level MPI_THREAD_SINGLE. Is
> > enable-mpi-thread-multiple required even for
> > MPI_THREAD_FUNNELED/MPI_THREAD_SERIALIZED?
> >
> > This question has been asked before:
> > http://www.open-mpi.org/community/lists/users/2011/05/16451.php but I
> > couldn't find an answer.
> >
> > Roland
> >
> > --
> > ORNL/UT Center for Molecular Biophysics cmb.ornl.gov
> > 865-241-1537, ORNL PO BOX 2008 MS6309
> >
> > _______________________________________________
> > users mailing list
> > users_at_[hidden]
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
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>

-- 
ORNL/UT Center for Molecular Biophysics cmb.ornl.gov
865-241-1537, ORNL PO BOX 2008 MS6309