Ok Brice, thanks very much for your explanations. But I don't understand why a process inherits core bound of his threads according to your example:
>It worked because you never mixed it with single thread binding. If you bind process X to >coreA and then thread Y of process X to coreB, what you should now see with get_cpubind is >that process X is now bound to cores A+B, thread Y to B, and all other threads to A. 2011/9/12 Brice Goglin <brice.gog...@inria.fr> > Le 12/09/2011 14:17, Gabriele Fatigati a écrit : > > Mm, and why? In a hybrid code ( MPI + OpenMP), my idea is to bind a > > single MPI process in one core, and his threads in other cores. > > Otherwise I have all threads that runs on a single core. > > > > The usual way to do that is to first bind the entire process to all > cores available to all its thread and then bind each thread to a single > core. > > For instance, if doing Open MPI + OpenMP with one process per socket > * you pass --bind-to-socket on the mpirun/mpiexec command-line > * when the MPI process starts, the OpenMP runtime calls something like > get_cpubind to find out how many cores were given to it > * it creates the exact same number of OpenMP threads and bind one of > them on each core > > Brice > > _______________________________________________ > hwloc-users mailing list > hwloc-us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users > -- Ing. Gabriele Fatigati HPC specialist SuperComputing Applications and Innovation Department Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy www.cineca.it Tel: +39 051 6171722 g.fatigati [AT] cineca.it
