A follow-up question (and pardon if this sounds stupid) is this: If I want to make my process multithreaded, BUT only one thread has anything to do with MPI (for example, using OpenMP inside MPI), then the results will be correct EVEN IF #1 or #2 of Eugene holds true. Is this correct?
Thanks Durga On Tue, Mar 8, 2011 at 12:34 PM, Eugene Loh <eugene....@oracle.com> wrote: > Let's say you have multi-threaded MPI processes, you request > MPI_THREAD_MULTIPLE and get MPI_THREAD_MULTIPLE, and you use the self,sm,tcp > BTLs (which have some degree of threading support). Is it okay to have an > [MPI_Isend|MPI_Irecv] on one thread be completed by an MPI_Wait on another > thread? I'm assuming some sort of synchronization and memory barrier/flush > in between to protect against funny race conditions. > > If it makes things any easier on you, we can do this multiple-choice style: > > 1) Forbidden by the MPI standard. > 2) Not forbidden by the MPI standard, but will not work with OMPI (not even > with the BTLs that claim to be multi-threaded). > 3) Works well with OMPI (provided you use a BTL that's multi-threaded). > > It's looking like #2 to me, but I'm not sure. > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
