To run a hybrid MPI/OpenMP code on a hyperthreaded machine with 24 virtual cores, I've been using -n 12 --cpus-per-proc 2 so I can use OMP_NUM_THREADS=2
I now see that --cpus-per-proc is deprecated in favour of --map-by, but I've been struggling to find a conversion as the --map-by documentation is not very clear. What should I use to bind 2 virtual cores to each process? After I use -n 12 --cpus-per-proc 2 I get A request was made to bind to that would result in binding more processes than cpus on a resource: Bind to: CORE Node: mic1 #processes: 2 #cpus: 1 and suggests I need an override option But this doesn't to match my request for 2 cores per process, almost the reverse, having 2 processes per core. I don't think I'm overloading my virtual cores anyway John
