Hello *, I would like to understand in more detail how much time some collective communication calls really spend waiting for the last process to enter. I know this can be done by logging entry times for each process, but I wonder if there is a better and more efficient way.
The peruse interface allows exactly that for send/recv communication (see http://www.open-mpi.org/papers/euro-pvmmpi-2006-peruse/). Unfortunately the current peruse specification (http://www.mpi-peruse.org/current_peruse_spec.pdf) does not cover collectives (but mentions them explicitly for future extensions). Does anyone know if there is a plan to go ahead with MPI peruse for collectives (in general and specifically in OpenMPI)? Are there hooks in the OpenMPI collective's code which could be used to hand-wire similar functionality? Thanks, Manfred -- Manfred Mücke rlcta.univie.ac.at Research Lab Computational Technologies and Applications
