Thanks for the explanation. I am using GigEth + Open MPI and the
buffered MPI_BSend. I had already noticed that top behaved differently
on another cluster with Infinibandb + MPICH.
So the only option to find out how much time each process is waiting
around seems to be to profile the code.
Top always shows all the paralell processes at 100% in the %CPU field,
although some of the time these must be waiting for a communication to
complete. How can I see actual processing as opposed to waiting at a
barrier?
Thanks,
Tiago
Hi,
I have a Multiple Program Multiple Data with three programs running in
parallel, say A, B and C. C is much slower so in order to balance the
load I want to parallelize C into C0 to Cn (SPMD). There are very
frequent communications between Ci processes and not so frequent, but
still mu
