Thanks for the clarification, Jeff.
Andrei,
MPIX_Query_cuda_support indeed just returns the value of OPAL_CUDA_SUPPORT
which is set to one if configure included --with-cuda.
/* If CUDA-aware support is configured in, return 1. Otherwise, return 0.
* This API may be extended to return more features in the future. */
int MPIX_Query_cuda_support(void)
{
return OPAL_CUDA_SUPPORT;
}
You can see the details of how OPAL_CUDA_SUPPORT is set in
root_dir/config/opal_check_cuda.m4
In summary, you could use MPIX_Query_cuda_support in your application to
check during runtime or you could check ompi_info to see if the build was
configured correctly --with-cuda before running a cuda-aware MPI
application.
On Tue, Oct 30, 2018 at 1:42 PM Jeff Squyres (jsquyres) <jsquy...@cisco.com>
wrote:
> Oh, I should clarify: that MPIX_Query_cuda_support() function is always
> present in Open MPI -- even if you don't compile with CUDA support.
>
> That's kinda the point / it's probably obvious, but I thought I would
> clarify, anyway. :-)
>
>
> > On Oct 30, 2018, at 4:29 PM, Akshay Venkatesh <akshay.v.3...@gmail.com>
> wrote:
> >
> > +1 to what Jeff said.
> >
> > So you would need --with-cuda pointing to a cuda installation to have
> cuda-awareness in OpenMPI.
> >
> > On Tue, Oct 30, 2018 at 12:47 PM Jeff Squyres (jsquyres) via users <
> users@lists.open-mpi.org> wrote:
> > The "Configure command line" shows you the command line that was given
> to "configure" when building Open MPI.
> >
> > The "MPI extensions" line just indicates which Open MPI "extensions"
> were built.
> >
> > CUDA is one of the possible extensions that can get built.
> >
> > The CUDA Open MPI extension is actually an API call that will tell you
> if your Open MPI has CUDA support:
> >
> > https://www.open-mpi.org/doc/v3.1/man3/MPIX_Query_cuda_support.3.php
> >
> >
> >
> >
> > > On Oct 30, 2018, at 3:14 PM, Akshay Venkatesh <akshay.v.3...@gmail.com>
> wrote:
> > >
> > > The first one is the critical one. If the build was not configured
> --with-cuda, then it's unlikely cuda-aware MPI is supported.
> > >
> > > On Tue, Oct 30, 2018, 12:10 PM Andrei Berceanu <
> andreicberce...@gmail.com> wrote:
> > > Thanks! I tried both and
> > > ompi_info -a | grep "\-with\-cuda" returns nothing, while
> > > ompi_info -a | grep "xtensions" returns
> > > MPI extensions: affinity, cuda
> > >
> > > It seems the two outputs are in conflict, what does that mean?
> > >
> > >
> > > On Tue, Oct 30, 2018 at 8:50 PM Akshay Venkatesh <
> akshay.v.3...@gmail.com> wrote:
> > > Andrei,
> > >
> > > I generally check with one of these two:
> > >
> > > $ ompi_info -a | grep "\-with\-cuda"
> > > Configure command line: '--prefix=$HOME/ompi/build-cuda'
> '--enable-mpirun-prefix-by-default' '--with-cuda=/usr/local/cuda'
> '--with-ucx=$HOME/ucx-github/build'
> '--with-ucx-libdir=$HOME/ucx-github/build/lib' '--enable-debug'
> '--enable-mem-debug' '--enable-mpi-fortran=no' '--disable-oshmem'
> '--enable-install-libpmix' '--with-ompi-pmix-rte'
> > >
> > > $ ompi_info -a | grep "xtensions"
> > > MPI extensions: affinity, cuda, pcollreq
> > >
> > >
> > > On Tue, Oct 30, 2018 at 11:40 AM Andrei Berceanu <
> andreicberce...@gmail.com> wrote:
> > > Hi all,
> > >
> > > I am using openmpi@3.1.2 on an Ubuntu@16.04.5 box, how can I check if
> it has CUDA support or not?
> > >
> > > Best,
> > > Andrei
> > > _______________________________________________
> > > users mailing list
> > > users@lists.open-mpi.org
> > > https://lists.open-mpi.org/mailman/listinfo/users
> > >
> > >
> > > --
> > > -Akshay
> > > NVIDIA
> > > _______________________________________________
> > > users mailing list
> > > users@lists.open-mpi.org
> > > https://lists.open-mpi.org/mailman/listinfo/users
> > > _______________________________________________
> > > users mailing list
> > > users@lists.open-mpi.org
> > > https://lists.open-mpi.org/mailman/listinfo/users
> > > _______________________________________________
> > > users mailing list
> > > users@lists.open-mpi.org
> > > https://lists.open-mpi.org/mailman/listinfo/users
> >
> >
> > --
> > Jeff Squyres
> > jsquy...@cisco.com
> >
> > _______________________________________________
> > users mailing list
> > users@lists.open-mpi.org
> > https://lists.open-mpi.org/mailman/listinfo/users
> >
> >
> > --
> > -Akshay
> > NVIDIA
>
>
> --
> Jeff Squyres
> jsquy...@cisco.com
>
>
--
-Akshay
NVIDIA
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