I would like to know what are the algorithms used in MPI_BCast() in the OpenMPI implementation.
For example, in MPICH2, depending on the number of processes and the size of data to broadcast, the broadcasting algorithm used can be different : a binomial tree if the message is short or MPI_Scatter followed by MPI_AllGather if the message to broadcast is long.
Is it the same for OpenMPI ?
It doesn't seem to be the case since the broadcasting time is different when I use OpenMPI or MPICH2.
Thanks for your help,