Using hwloc physical ID to build MPI rankfile

Question

I\'m not sure how to use the physical IDs that I\'ve retrieved from hwloc. For example, I see the following, but if I place rank 0=10.0.2.4 slot=1:8 in the rank

Answer 1

So there is a PU numbered 23, but no core with this number, so if there is an error referencing number 23 then MPI is trying to get a core.

# No errors, so this is referencing a PU
rank 1=10.0.2.4 slot=1:p23
# No errors, so we are referencing a PU
rank 1=10.0.2.4 slot=p1:p23
# Error! We might be referencing a core
rank 1=10.0.2.4 slot=p1:23
# No error, we are probably referencing physical socket 1 and physical core 8
rank 1=10.0.2.4 slot=p1:8