Ah, yes - I know what the problem is. We weren’t expecting a PE value of 1 - the logic is looking expressly for values > 1 as we hadn’t anticipated this use-case.
I can make that change. I’m off to a workshop for the next day or so, but can probably do this on the plane. > On Feb 15, 2017, at 3:17 AM, Mark Dixon <m.c.di...@leeds.ac.uk> wrote: > > Hi, > > When combining OpenMPI 2.0.2 with OpenMP, I'm interested in launching a > number of ranks and allocating a number of cores to each rank. Using "-map-by > socket:PE=<num>", switching to "-map-by node:PE=<num>" if I want to allocate > more than a single socket to a rank, seems to do what I want. > > Except for "-map-by socket:PE=1". That seems to allocate an entire socket to > each rank instead of a single core. Here's the output of a test program on a > dual socket non-hyperthreading system that reports rank core bindings (odd > cores on one socket, even on the other): > > $ mpirun -np 2 -map-by socket:PE=1 ./report_binding > Rank 0 bound somehost.somewhere: 0 2 4 6 8 10 12 14 16 18 20 22 > Rank 1 bound somehost.somewhere: 1 3 5 7 9 11 13 15 17 19 21 23 > > $ mpirun -np 2 -map-by socket:PE=2 ./report_binding > Rank 0 bound somehost.somewhere: 0 2 > Rank 1 bound somehost.somewhere: 1 3 > > $ mpirun -np 2 -map-by socket:PE=3 ./report_binding > Rank 0 bound somehost.somewhere: 0 2 4 > Rank 1 bound somehost.somewhere: 1 3 5 > > $ mpirun -np 2 -map-by socket:PE=4 ./report_binding > Rank 0 bound somehost.somewhere: 0 2 4 6 > Rank 1 bound somehost.somewhere: 1 3 5 7 > > I get the same result if I change "socket" to "numa". Changing "socket" to > either "core", "node" or "slot" binds each rank to a single core (good), but > doesn't round-robin ranks across sockets like "socket" does (bad). > > Is "-map-by socket:PE=1" doing the right thing, please? I tried reading the > man page but I couldn't work out what the expected behaviour is :o > > Cheers, > > Mark > > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users _______________________________________________ users mailing list users@lists.open-mpi.org https://rfd.newmexicoconsortium.org/mailman/listinfo/users
