On Jan 6, 2012, at 7:02 AM, Nick Mathewson wrote: > On Fri, Jan 6, 2012 at 7:24 AM, Ralph Castain <r...@open-mpi.org> wrote: >> If it helps, I have now confirmed that I *can* activate the t2 event during >> the t1func callback in my example *provided* I called event_assign on it >> prior to entering event_base_loop. It is also okay for me to event_add the >> t2 event during the callback - I am simply not allowed to event_assign *and* >> activate it there. >> >> However, it is okay to assign the event during the callback so long as I >> don't activate it until after I return. >> >> Seems a little strange to me - is this the intended behavior? > > Well, no, of course not. > > Looking at your code, the only weird thing I see at first glance is > that you are calling event_add() on t1 and t2 -- you shouldn't be > doing that. event_add() is only for events that you want libevent to > poll or wait for, but waiting for EV_WRITE on fd -1 isn't > well-defined. If you want to activate them yourself with > event_active(), there's no need to event_add() them. > > That shouldn't be causing this problem, though, I think. (Unless it is?)
BINGO! Indeed, event_add was the source of the trouble. My bad for not understanding when event_add was required. > > I just tried your test programs, though, and they worked okay for me > on OSX and linux, using Libevent 2.0.13-stable and Libevent > 2.0.14-stable. > > What platform are you running your tests on? Have you tried other > platforms too? Does the outcome depend on which libevent backend is > in use? Have you tried this with an unpatched Libevent, just to > confirm that it's not introduced by any openmpi patches? FWICT, it is a corruption issue, and so it does indeed depend on platform and backend - just a question of what memory location gets trounced. FWIW, I was conducting my tests on OSX and linux as well, using OMPI with 2.0.13 underneath. I think the difference in our results is due to the location issue - I suspect that you might also hit a problem if we continued chaining events long enough, but I haven't confirmed it. Also fwiw: the OMPI changes are confined to configuration/Makefile areas - we actually don't fiddle with the libevent code itself other than a couple of places where we test for stdbool.h before including it. Thanks Nick! Ralph > > yrs, > -- > Nick > *********************************************************************** > To unsubscribe, send an e-mail to majord...@freehaven.net with > unsubscribe libevent-users in the body. *********************************************************************** To unsubscribe, send an e-mail to majord...@freehaven.net with unsubscribe libevent-users in the body.
