Thanks, I think that will be very useful.

Best,
Udayanga


On Wed, Jan 9, 2019 at 1:39 PM Jeff Squyres (jsquyres) via users <
users@lists.open-mpi.org> wrote:

> You can set this MCA var on a site-wide basis in a file:
>
>     https://www.open-mpi.org/faq/?category=tuning#setting-mca-params
>
>
>
> > On Jan 9, 2019, at 1:18 PM, Udayanga Wickramasinghe <uswic...@iu.edu>
> wrote:
> >
> > Thanks. Yes, I am aware of that however, I currently have a requirement
> to increase the default.
> >
> > Best,
> > Udayanga
> >
> > On Wed, Jan 9, 2019 at 9:10 AM Nathan Hjelm via users <
> users@lists.open-mpi.org> wrote:
> > If you need to support more attachments you can set the value of that
> variable either by setting:
> >
> > Environment:
> >
> > OMPI_MCA_osc_rdma_max_attach
> >
> >
> > mpirun command line:
> >
> > —mca osc_rdma_max_attach
> >
> >
> > Keep in mind that each attachment may use an underlying hardware
> resource that may be easy to exhaust (hence the low default limit). It is
> recommended to keep the total number as small as possible.
> >
> > -Nathan
> >
> > > On Jan 8, 2019, at 9:36 PM, Udayanga Wickramasinghe <uswic...@iu.edu>
> wrote:
> > >
> > > Hi,
> > > I am running into an issue in open-mpi where it crashes abruptly
> during MPI_WIN_ATTACH.
> > > [nid00307:25463] *** An error occurred in MPI_Win_attach
> > > [nid00307:25463] *** reported by process
> [140736284524545,140728898420736]
> > > [nid00307:25463] *** on win rdma window 3
> > > [nid00307:25463] *** MPI_ERR_RMA_ATTACH: Could not attach RMA segment
> > > [nid00307:25463] *** MPI_ERRORS_ARE_FATAL (processes in this win will
> now abort,
> > > [nid00307:25463] ***    and potentially your MPI job)
> > >
> > > Looking more into this issue, it seems like open-mpi has a restriction
> on the maximum number of segments attached to 32. (OpenMpi3.0 spec doesn't
> spec doesn't say a lot about this scenario --"The argument win must be a
> window that was created with MPI_WIN_CREATE_DYNAMIC. Multiple (but
> nonoverlapping) memory regions may be attached to the same window")
> > >
> > > To workaround this, I have temporarily modified the variable
> mca_osc_rdma_component.max_attach. Is there any way to configure this in
> open-mpi?
> > >
> > > Thanks
> > > Udayanga
> > > _______________________________________________
> > > 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
> > _______________________________________________
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>
>
> --
> Jeff Squyres
> jsquy...@cisco.com
>
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