Why is this allocated statically? I dont understand the difficulty of a dynamically allocates and thus unrestricted implementation. Is there some performance advantage to a bounded static allocation? Or is it that you use O(n) lookups and need to keep n small to avoid exposing that to users?
I have usage models with thousands of attached segments, hence need to understand how bad this will be with Open-MPI (yes I can amortize overhead but it’s a pain). Thanks, Jeff On Wed, Jan 9, 2019 at 8:12 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 -- Jeff Hammond jeff.scie...@gmail.com http://jeffhammond.github.io/
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