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From: Barrett, Brian W (bwbarre_at_[hidden])
Date: 2010-01-28 21:24:04

Jeff -

I think the idea is ok, but I think the name needs some thought. There's currently two ways to have the lower layers be thread safe -- enabling MPI threads or progress threads. The two can be done independently -- you can disable MPI threads and still enable thread support by enabling progress threads.

So either that behavior would need to change or we need a better name (in my opinion...).


On Jan 28, 2010, at 8:53 PM, Jeff Squyres wrote:

> WHAT: Rename --enable-mpi-threads and ENABLE_MPI_THREADS to --enable-thread-safety and ENABLE_THREAD_SAFETY, respectively (--enable-mpi-threads will be maintained as a synonym to --enable-thread-safety for backwards compat, of course).
> WHY: Other projects are starting to use ORTE and OPAL without OMPI. The fact that thread safety in OPAL and ORTE requires a configure switch with "mpi" in the name is very non-intuitive.
> WHERE: A bunch of places in the code; see attached patch.
> WHEN: Next Friday COB
> TIMEOUT: COB, Friday, Feb 5, 2010
> ------------------------
> More details:
> Cisco is starting to investigate using ORTE and OPAL in various threading scenarios -- without the OMPI layer. The fact that you need to enable thread safety in ORTE/OPAL with a configure switch that has the word "mpi" in it is extremely counter-intuitive (it bit some of our engineers very badly, and they were mighty annoyed!!).
> Since this functionality actually has nothing to do with MPI (it's actually the other way around -- MPI_THREAD_MULTIPLE needs this functionality), we really should rename this switch and the corresponding AC_DEFINE -- I suggest:
> --enable|disable-thread-safety
> Of course, we need to keep the configure switch "--enable|disable-mpi-threads" for backwards compatibility, so that can be a synonym to --enable-thread-safety.
> See the attached patch (the biggest change is in opal/config/opal_config_threads.m4). If there are no objections, I'll commit this next Friday COB.
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> <opal-thread-safety.diff>_______________________________________________
> devel mailing list
> devel_at_[hidden]

  Brian W. Barrett
  Dept. 1423: Scalable System Software
  Sandia National Laboratories