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From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2007-11-01 09:25:03

On Oct 31, 2007, at 9:52 PM, Neeraj Chourasia wrote:

> but the program is running on TCP interconnect with same
> datasize and also on IB with small datasize say 1MB. So i dont
> think problem is in OpenMPI, it has to do something with IB logic,
> which probably doesnt work well with threads.

Open MPi's TCP nominally supports threads, but I'd be surprised if it
works consistently (i.e., it has not been tested thoroughly). The
Open MPI IB code definitely does not yet work with threads.

> I also tried the program with MPI_THREAD_SERIALIZED, but in vain.

Open MPI currently treats this as no different than THREAD_SINGLE;
the problem is that you'll still have multiple different threads
calling MPI simultaneously with your program.

> When is the version 1.3 scheduled to be released? Would it fix
> such issues?

No. We had been planning to make THREAD_MULTIPLE support available
in the 1.3 series, but there honestly has not been enough customer
demand for it such that we could not justify putting the resources /
spending the time to finish it in Open MPI. :-( THREAD_MULTIPLE is
still on the long-term roadmap, but it will not be included in the
1.4 series.

Jeff Squyres
Cisco Systems