> On Apr 10, 2017, at 1:37 AM, Reuti <re...@staff.uni-marburg.de> wrote: > >> >> Am 10.04.2017 um 01:58 schrieb r...@open-mpi.org <mailto:r...@open-mpi.org>: >> >> 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. > > Yes, I see. But only if libnuma was compiled in AFAICS. > > >> 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. > > Mmh - can I spot a difference in --report-bindings between these two? To me > both looks like being bound to socket.
You won’t see a difference if the NUMA and socket are identical in terms of the cores they cover. > > -- Reuti > > >> 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 >> > > _______________________________________________ > users mailing list > users@lists.open-mpi.org <mailto:users@lists.open-mpi.org> > https://rfd.newmexicoconsortium.org/mailman/listinfo/users > <https://rfd.newmexicoconsortium.org/mailman/listinfo/users>
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