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From: smairal_at_[hidden]
Date: 2007-05-27 15:55:05


Thanks a lot guys for your help. I am also trying a design where I have
one thread doing MPI and others doing some computation (non-MPI). If I
have only MPI_THREAD_SINGLE enabled for OpenMPI, can I still implement
this kind of a design or there would be issues with threads in OpenMPI.

-Thanks and Regards,
Sarang.

Quoting "Brian W. Barrett" <bbarrett_at_[hidden]>:

> There are two ways you can find out if an Open MPI build has
> MPI_THREAD_MULTIPLE support:
>
> * On the command line: You can run "ompi_info | grep Thread". If you
> see
> mpi: no, the build doesn't support MPI_THREAD_MULTIPLE. If you see
> mpi:
> yes, the build does support MPI_THREAD_MULTIPLE.
>
> * At run-time. As mentioned below, if you request
> MPI_THREAD_MULTIPLE and
> provided is only MPI_THREAD_SINGLE, then Open MPI does not have
> MPI_THREAD_MULTIPLE support.
>
>
> Good luck,
>
> Brian
>
> > You are already there. the fact that MPI_Thread_init only provide
> > MPI_THREAD_SINGLE shows that MPI_THREAD_MULTIPLE is NOT enabled in
> the
> > library binary that you're using. Although MPI_THREAD_MULTIPLE is
> > implemented in the library source code, it is only lightly tested,
> so it
> > is
> > not enabled by default.
> >
> > To enable MPI_THREAD_MULTIPLE, you need to recompile the library by
> first
> > including --enable-mpi-threads as one of the parameters when you
> rerun
> > ./configure as the first step of recompiling the library.
> >
> >
> >
> > On 5/27/07, smairal_at_[hidden] <smairal_at_[hidden]> wrote:
> >>
> >> Hi,
> >> I want to use threads with OpenMPI such that the threads
> would
> >> be able to call MPI functions. For this purpose, I am using
> >> MPI_Init_thread with MPI_THREAD_MULTIPLE option. But this function
> call
> >> returns MPI_THREAD_SINGLE in the "provided" parameter indicating
> that
> >> MPI_THREAD_MULTIPLE is not configured. Somewhere it is mentioned
> that
> >> OpenMPI needs to be configured with --enable-mpi-threads inorder
> to use
> >> MPI_THREAD_MULTIPLE. If true, is it possible to know whether the
> >> OpenMPI (1.1.2)which I have already configured, has the option
> >> "--enable-mpi-threads" already configured or not? Also, how easy
> or
> >> difficult is it to configure --enable-mpi-threads option?
> >> Please share some information on this.
> >>
> >> -Thanks and Regards,
> >> Sarang.
> >>
> >>
> >> _______________________________________________
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> >>
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