MPI Python not enough slots

1
votes

I'm currently new in using MPI for python with Open MPI and I have the following issue :

When I try to run a simple script with mpiexec -np 7 mpitest.py I have the following error :

There are not enough slots available in the system to satisfy the 7 slots that were requested by the application: python Either request fewer slots for your application, or make more slots available for use.

I don't understand, I have a 12 processor computer with 6 core per socket (1 socket per processor), so this would mean I would be able to run up to 72 threads but OpenMPI get stuck at 6.

Any idea how to take advantage of all processors ?

1
pythonmpiopenmpi
This is very odd... which Open MPI version ? What does mpirun --report-bindings -np 3 hostname says ? - Gilles Gouaillardet
1 socket per processor does not make sense. How many nodes ? Socket per node ? Core per socket ? Thread per core ? If hwloc is installed, can you run lstopo ? - Gilles Gouaillardet

1 Answers

0
votes

For newer versions of MPI, oversubscribing can help. Use the --oversubscribe switch as follows:

mpiexec --oversubscribe -np 7 mpitest.py