With OMPI 1.10.2 and earlier on Infiniband, IMB generally spins with no output for the barrier benchmark if you run it with algorithm 5, i.e.
mpirun --mca coll_tuned_use_dynamic_rules 1 --mca coll_tuned_barrier_algorithm 5 IMB-MPI1 barrier This is "two proc only". Does that mean it will only work for two processes (which seems true experimentally)? If so, should it report an error if used with more?
