Usually, when you want to listen to two kinds of event, you use poll/select on Unix (or epoll on Linux). This strategy doesn't work for MPI events because MPI doesn't provide a Unix file descriptor to pass to poll/select/epoll. One work-around is to have one thread listen to MPI events. When it receives your MPI message, it writes something into a pipe. Then your main thread uses poll/select/epoll to listen to your socket and to this pipe at the same time.
Another solution is to not busy polling alternatively on both kinds of them: MPI_Test*() on your communicator, then non-blocking read() on your socket, then MPI_Test(), etc. Works but wastes CPU cycles. Fortunately MPI often uses busy polling when waiting for messages anyway, so not sure it matters. Brice Le 25/06/2017 20:08, Trevour Spencer a écrit : > Dear all, > I have not yet found a solution for waiting for an event (incoming > message) to occur either on a TCP socket or on a MPI communicator. I > wish I could receive some comments from you MPI experts. > If my question was unclear, I found the same problem described on the > MPICH list two years ago: > https://lists.mpich.org/pipermail/discuss/2015-June/004049.html > He received no reply either. > > Is the question stupid for some reason, is the answer trivial, or is > there no solution to this problem? > > Cheers > Trevour > > 2017-06-20 20:15 GMT+02:00 Trevour Spencer <trevourspen...@gmail.com > <mailto:trevourspen...@gmail.com>>: > > Dear all, > I am looking for a solution to receive messages either via MPI or > via a TCP socket, whichever arrives next. > > Using the select() method as described for example at > http://developerweb.net/viewtopic.php?id=2933 > <http://developerweb.net/viewtopic.php?id=2933>, I can have my > code wait until any of a given set of TCP sockets receives some data. > > Does a similar solution exist, such that the code waits until data > is available either from an MPI communicator or from a TCP socket? > > Cheers > Trevour > > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virenfrei. www.avast.com > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > > > > > > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users
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