Let me try to clarify. If you launch a job that has only 1 or 2 processes in it (total), then we bind to core by default. This is done because a job that small is almost always some kind of benchmark.
If there are more than 2 processes in the job (total), then we default to binding to NUMA (if NUMA’s are present - otherwise, to socket) across the entire job. You can always override these behaviors. > On Apr 9, 2017, at 3:45 PM, Reuti <re...@staff.uni-marburg.de> wrote: > >>> But I can't see a binding by core for number of processes <= 2. Does it >>> mean 2 per node or 2 overall for the `mpiexec`? >> >> It’s 2 processes overall > > Having a round-robin allocation in the cluster, this might not be what was > intended (to bind only one or two cores per exechost)? > > Obviously the default changes (from --bind-to core to --bin-to socket), > whether I compiled Open MPI with or w/o libnuma (I wanted to get rid of the > warning in the output only – now it works). But "--bind-to core" I could also > use w/o libnuma and it worked, I got only that warning in addition about the > memory couldn't be bound. > > BTW: I always had to use -ldl when using `mpicc`. Now, that I compiled in > libnuma, this necessity is gone. > > -- Reuti > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users _______________________________________________ users mailing list users@lists.open-mpi.org https://rfd.newmexicoconsortium.org/mailman/listinfo/users
