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 <[email protected]> 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
> <[email protected]> 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 <[email protected]> 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
> > _______________________________________________
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> > https://lists.open-mpi.org/mailman/listinfo/users
>
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--
Jeff Squyres
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