On Sat, 2009-10-03 at 07:05 -0400, Jeff Squyres wrote: > That being said, if you just want to send a quick "notify" that an > event has occurred, you might want to use a specific tag and/or > communicator for these extraordinary messages. Then, when the event > occurs, send a very short message on this special tag/communicator > (potentially even a 0-byte message).
> You can MPI_TEST for > the completion of this short/0-byte receive very quickly. You can > then send the actual data of the event in a different non-blocking > receive that is only checked if the short "alert" message is received. In general I would say that Iprobe is a bad thing to use, as Jeff says post a receive in advance and then call test on this receive rather than using Iprobe. >From your description it sounds like a zero byte send is all you need which should be fast in all cases. Ashley, -- Ashley Pittman, Bath, UK. Padb - A parallel job inspection tool for cluster computing http://padb.pittman.org.uk
