> Am 10.04.2017 um 17:27 schrieb r...@open-mpi.org: > > >> 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: >>> >>> 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.
Ok, thx. >> >> -- 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 >> https://rfd.newmexicoconsortium.org/mailman/listinfo/users > > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users
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