On Wed, 16 Aug 2017, Renato Poli wrote: > > I added this call on the master process (id=0): >> vector<double> _sys_solution; /// in .hxx >> sys.solution->localize_to_one( _sys_solution ); >> >> The system got stuck, >> > > As I'd expect. The solution only gets filled on proc_id=0, but it's > still a collective operation: proc 0 is the only one receiving, but > every other processor is sending. >
A-há! It worked. Thanks. > > with all four processes with 100% processor usage. >> > > That's MPI busy-waiting. In real use cases, where you have at least > one core for every MPI rank and you're trying to run as fast as > possible, I guess it's the lowest latency thing to do, but I wish I > know how to turn it off and make mpich2 or openmpi use blocking waits > instead. Sometimes I have one processor stopped by gdb and the others > are just wasting CPU, sometimes I'd like to use N cores to run N*2 MPI > ranks for debugging purposes and I'd like them not to step on each > other's toes... > Can these processes simply be exit? In my case I simply do not need them anymore. Thanks Roy! Regards, Renato ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
