In the general case, MPI defines that you *have* to call one of the MPI_Test or MPI_Wait functions to finish the communication request. If you don't do so, you're basically leaking resources (e.g., memory).
In a single-threaded MPI implementation, the call to MPI_Test/MPI_Wait/etc. may be where the actual message passing progress occurs, too. If you don't want to block waiting for the communication, you can keep an array of outstanding MPI_Requests and call MPI_Testall() on them to allow MPI to make progress on them, but not block your application until all (or any) of them complete. > On Apr 3, 2015, at 3:43 AM, Matthieu Brucher <matthieu.bruc...@gmail.com> > wrote: > > Hi, > > I think you have to call either Wait or Test to make the communications move > forward in the general case. Some hardware may have a hardware thread that > makes the communication, but usually you have to make it "advance" yourself > by either calling Wait ot Test. > > Cheers, > > Matthieu > > 2015-04-03 5:48 GMT+01:00 Lei Shi <lei...@ku.edu>: > I want to use non-blocking send/rev MPI_Isend/MPI_Irev to do communication. > But in my case, I don't really care what kind of data I get or it is ready to > use or not. So I don't want to waste my time to do any synchronization by > calling MPI_Wait or etc API. > > But when I avoid calling MPI_Wait, my program is freezed several secs after > running some iterations (after multiple MPI_Isend/Irev callings), then > continues. It takes even more time than the case with MPI_Wait. So my > question is how to do a "true" non-blocking communication without waiting for > the data ready or not. Thanks. > > Sincerely Yours, > > Lei Shi > --------- > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26596.php > > > > -- > Information System Engineer, Ph.D. > Blog: http://matt.eifelle.com > LinkedIn: http://www.linkedin.com/in/matthieubrucher > Music band: http://liliejay.com/ > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/04/26598.php -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
