It isn't that simple. In some cases, THREAD_MULTIPLE works just fine. In some, it doesn't. Trying to devise logic that accurately detects when it does and doesn't work would be extremely difficult, and in many cases application-dependent. If we disable it for everyone, then those who can make it work get upset.
We don't like the situation either :-( On Apr 28, 2014, at 8:03 AM, Jeffrey A Cummings <jeffrey.a.cummi...@aero.org> wrote: > Wouldn't you save yourself work and your users confusion if you disabled > options that don't currently work? > > > Jeffrey A. Cummings > Engineering Specialist > Performance Modeling and Analysis Department > Systems Analysis and Simulation Subdivision > Systems Engineering Division > Engineering and Technology Group > The Aerospace Corporation > 571-307-4220 > jeffrey.a.cummi...@aero.org > > > > From: Ralph Castain <r...@open-mpi.org> > To: Open MPI Users <us...@open-mpi.org>, > Date: 04/25/2014 05:40 PM > Subject: Re: [OMPI users] Deadlocks and warnings from libevent when > using MPI_THREAD_MULTIPLE > Sent by: "users" <users-boun...@open-mpi.org> > > > > We don't fully support THREAD_MULTIPLE, and most definitely not when using > IB. We are planning on extending that coverage in the 1.9 series > > > On Apr 25, 2014, at 2:22 PM, Markus Wittmann <markus.wittm...@fau.de> wrote: > > > Hi everyone, > > > > I'm using the current Open MPI 1.8.1 release and observe > > non-deterministic deadlocks and warnings from libevent when using > > MPI_THREAD_MULTIPLE. Open MPI has been configured with > > --enable-mpi-thread-multiple --with-tm --with-verbs (see attached > > config.log) > > > > Attached is a sample application that spawns a thread for each process > > after MPI_Init_thread has been called. The thread then calls MPI_Recv > > which blocks until the matching MPI_Send is called just before > > MPI_Finalize is called in the main thread. (AFAIK MPICH uses such kind > > of facility to implement a progress thread) Meanwhile the main thread > > exchanges data with its right/left neighbor via ISend/IRecv. > > > > I only see this, when the MPI processes run on separate nodes like in > > the following: > > > > $ mpiexec -n 2 -map-by node ./test > > [0] isend/irecv. > > [0] progress thread... > > [0] waitall. > > [warn] opal_libevent2021_event_base_loop: reentrant invocation. Only one > > event_base_loop can run on each event_base at once. > > [1] isend/irecv. > > [1] progress thread... > > [1] waitall. > > [warn] opal_libevent2021_event_base_loop: reentrant invocation. Only one > > event_base_loop can run on each event_base at once. > > > > <no further output...> > > > > Can anybody confirm this? > > > > Best regards, > > Markus > > > > -- > > Markus Wittmann, HPC Services > > Friedrich-Alexander-Universität Erlangen-Nürnberg > > Regionales Rechenzentrum Erlangen (RRZE) > > Martensstrasse 1, 91058 Erlangen, Germany > > http://www.rrze.fau.de/hpc/ > > <info.tar.bz2><test.c>_______________________________________________ > > users mailing list > > us...@open-mpi.org > > http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
