On Mar 8, 2011, at 12:34 PM, Eugene Loh 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).
I believe the current answer is #2, but it would be great if the answer could change to be a variant of #3: 3) Works well with OMPI (provided you use a BTL that's safe to use with MPI_THREAD_MULTIPLE) (i.e., the BTL doesn't have to be multi-threaded, itself) -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
