On Sep 12, 2012, at 4:57 AM, "John R. Cary" <c...@txcorp.com> wrote:
> I do want in fact to bind first to one HT of each core > before binding to two HTs of one core. So that will > be possible in 1.7? Yes - you can get a copy of the 1.7 nightly tarball and experiment with it in advance, if you like. You'll want mpirun --map-by core --bind-to hwthread .... Add --report-bindings to see what happens, but I believe that will do what you want. You'll map one process to each core, and bind it to only the first hwthread on that core. Let me know either way - if it doesn't, we have time to adjust it. > > Thx....John > > On 9/11/12 11:19 PM, Ralph Castain wrote: >> Not entirely sure I know what you mean. If you are talking about running >> without specifying binding, then it makes no difference - we'll run wherever >> the OS puts us, so you would need to tell the OS not to use the virtual >> cores (i.e., disable HT). >> >> If you are talking about binding, then pre-1.7 releases all bind to core at >> the lowest level. On a hyperthread-enabled machine, that binds you to both >> HT's of a core. Starting with the upcoming 1.7 release, you can bind to the >> separate HTs, but that doesn't sound like something you want to do. >> >> HTH >> Ralph >> >> >> On Sep 11, 2012, at 6:34 PM, John R. Cary <c...@txcorp.com> wrote: >> >>> Our code gets little benefit from using virtual cores (hyperthreading), >>> so when we run with mpiexec on an 8 real plus 8 virtual machine, we >>> would like to be certain that it uses only the 8 real cores. >>> >>> Is there a way to do this with openmpi? >>> >>> Thx....John >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/users >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users >> > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
