Hi Samuel, how the topology gave by lstopo is built? In particolar, how the logical index P# are initialized?
2011/8/4 Samuel Thibault <samuel.thiba...@inria.fr> > Hello, > > Gabriele Fatigati, le Mon 01 Aug 2011 12:32:44 +0200, a écrit : > > So, are not physically near. I aspect that with Hyperthreading, and 2 > hardware > > threads each core, PU P#0 and PU P#1 are on the same core. > > Since these are P#0 and 1, they may not be indeed (physical indexes). > That's the whole problem of the indexes provided by operating systems. > > Fortunately, > > > If is it not true, > > using in a OMP PARALLEL region with 2 software threads: > > > > $ pragma omp paralle num_threads(2) > > > > tid= omp_get_thread_num(); > > > > hwloc_obj_t core = hwloc_get_obj_by_type(topology, HWLOC_OBJ_PU, tid); > > hwloc_cpuset_t set = hwloc_bitmap_dup(core->cpuset); > > hwloc_bitmap_singlify(set); > > > > hwloc_set_cpubind(topology, set, HWLOC_CPUBIND_THREAD); > > > > > > > > i would bind thread 0 on PU P#0 and thread 1 on PU P#1, supposing are > > physically near. > > No, because hwloc functions do not use physical, but logical indexes, > which it computes according to the topology. Use lstopo --top to check > the actual binding being used. > > Samuel > _______________________________________________ > 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
