Looks like this is a scif bug. From the documentation: scif_poll() waits for one of a set of endpoints to become ready to perform an I/O operation; it is syntactically and semantically very similar to poll() . The SCIF functions on which scif_poll() waits are scif_accept(), scif_send(), and scif_recv(). Consult the SCIF API reference manuals for details on scif_poll() usage.
So, if it is indeed similar to poll() it should wake up when the file descriptor is closed. Since that is not the case I will look through the documentation and see if there is a way other than pthread_cancel. -Nathan On Wed, May 14, 2014 at 11:18:05AM +0900, Gilles Gouaillardet wrote: > Folks, > > i would like to comment on r31738 : > > > There is no reason to cancel the listening thread. It should die > > automatically when the file descriptor is closed. > i could not agree more > > It is sufficient to just wait for the thread to exit with pthread join. > unfortunatly, at least in my test environment (an outdated MPSS 2.1) it > is *not* :-( > > this is what i described in #4615 > https://svn.open-mpi.org/trac/ompi/ticket/4615 > in which i attached scif_hang.c that evidences that (at least in my > environment) > scif_poll(...) does *not* return after scif_close(...) is closed, and > hence the scif pthread never ends. > > this is likely a bug in MPSS and it might have been fixed in earlier > release. > > Nathan, could you try scif_hang in your environment and report the MPSS > version you are running ? > > > bottom line, and once again, in my test environment, pthread_join (...) > without pthread_cancel(...) > might cause a hang when the btl/scif module is released. > > > assuming the bug is in old MPSS and has been fixed in recent releases, > what is the OpenMPI policy ? > a) test the MPSS version and call pthread_cancel() or do *not* call > pthread_join if buggy MPSS is detected ? > b) display an error/warning if a buggy MPSS is detected ? > c) do not call pthread_join at all ? /* SIGSEGV might occur with older > MPSS, it is in MPI_Finalize() so impact is limited */ > d) do nothing, let the btl/scif module hang, this is *not* an OpenMPI > problem after all ? > e) something else ? > > Gilles > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2014/05/14786.php
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