Dear Heinrich, I also had noted this change in behaviour, I don't know whether this is intentional. It looks like openmpi does not want to do oversubscription by default anymore. You can get the old behaviour back by using the --map-by option:
mpirun --map-by socket:OVERSUBSCRIBE -np 4 python -c "print 'hello'" Le 02/01/2017 à 20:37, Heinrich Schuchardt a écrit : > I am running on Intel Core i5-6300U CPU @ 2.40GHz. > /proc/cpuinfo reports 4 CPUs. http://ark.intel.com/fr/products/88190/Intel-Core-i5-6300U-Processor-3M-Cache-up-to-3_00-GHz Your CPU has 4 threads, but only 2 real cores. So the real limit for oversubscription is 2 rather than 4. > mpirun -np 2 --hostfile hostfile python -c "print 'hello'" > works fine. > > mpirun -np 4 --hostfile hostfile python -c "print 'hello'" > fails with > "There are not enough slots available in the system to satisfy the 4 slots" > > https://www.open-mpi.org/faq/?category=running#slots-without-hostfiles > describes that overprovisioning should work > > Best regards > > Heinrich Schuchardt Kind regards, Thibaut
