Hi, The version of Open MPI I'm using is mpiexec (OpenRTE) 1.6.5
It's what's offered on this smaller batch scheduling cluster at Oak Ridge (Sith to be exact). Running the ompi_info command, I get Thread support: posix (MPI_THREAD_MULTIPLE: no, progress: no) FT Checkpoint support: no (checkpoint thread: no) and in my MPI_Init_thread call, the provided flag is returned as MPI_THREAD_SINGLE. I was mainly concerned because we have a threaded middleware underneath to communicate across MPI worlds that also uses the IB infrastructure and verbs library, so I just wanted to get some clarity as to what exactly MPI_THREAD_SINGLE meant. Brian's answer seems to make perfect sense. Thanks! On Wed, Oct 23, 2013 at 1:47 PM, Jeff Hammond <jeff.scie...@gmail.com>wrote: > On Wed, Oct 23, 2013 at 12:02 PM, Barrett, Brian W <bwba...@sandia.gov> > wrote: > > On 10/22/13 10:23 AM, "Jai Dayal" <dayals...@gmail.com> wrote: > <snip> > > I'm asking because I'm using an open_mpi build ontop of infiniband, and > the > > maximum thread mode is MPI_THREAD_SINGLE. > > > > > > That doesn't seem right; which version of Open MPI are you using? > > The last time I looked at this, OpenMPI only supported > MPI_THREAD_SINGLE by default and if you ask for any higher thread > level, you get MPI_THREAD_MULTIPLE, which requires a configure-time > switch. > > Maybe something has changed dramatically more recently than I tested. > Squyres told me some thread-oriented refactoring was going on. All of > this was over a year ago so it is entirely reasonable for me to be > wrong about all of this. > > Jeff > > -- > Jeff Hammond > jeff.scie...@gmail.com > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >