OMPI will use as many slots as Torque tells it to. So if you qsub with ppn=2, then OMPI will use 2 slots per node; if you qsub with ppn=1, then OMPI will use 1 slot per node, etc.
OMPI defaults to -byslot scheduling, so if you qsub with ppn=2/OMPI uses 2 slots per node, OMPI will schedule MPI_COMM_WORLD ranks 0 and 1 on the first node, 2 and 3 on the next node, etc. There is not currently any diagnostic output that shows this; I can add it to my to-do list. > -----Original Message----- > From: users-boun...@open-mpi.org > [mailto:users-boun...@open-mpi.org] On Behalf Of Ogden, Jeffry Brandon > Sent: Friday, April 28, 2006 6:20 PM > To: us...@open-mpi.org > Subject: [OMPI users] Default number of slots when using Torque > > How does the orterun launch determine the default number of slots per > node when running in a Torque job? Is there debug output from orterun > that will show me this? > > Thanks. > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
