[MPICH] Difference between mpich2 logging and MPE logging

[Suman Kansakar]

What is the difference between MPICH2 logging (rlog) and the MPE
logging? It seems that when MPICH2 is compiled with options for MPICH2
logging, the MPE logging gets disabled.

I am trying to find the port numbers through which message passing is
happening between processes in each of the nodes (especially when
MPI_ALLREDUCE is being called) - is there a way to find this out
through MPE logging/tracing or MPICH2 logging?

Thanks.