[mpi-21] Ballot 4 - MPI_THREAD_FUNNELED - was Re: Attending, topics, etc

[Rolf Rabenseifner]

That's fine for me.

On Thu, 31 Jan 2008 10:27:59 -0500
 Richard Treumann <treumann_at_[hidden]> wrote:
>How about::
>MPI_THREAD_FUNNELED The process may be multi-threaded, but the application
>must insure that only the main thread makes MPI calls.
>
>
>Dick Treumann  -  MPI Team/TCEM
>IBM Systems & Technology Group
>Dept 0lva / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
>Tele (845) 433-7846         Fax (845) 433-8363
>
>
>mpi-21-bounces_at_[hidden] wrote on 01/31/2008 09:44:08 AM:
>
>> A simpler change which would seem to achieve the desired clarification
>> would be :-
>>
>>    MPI_THREAD_FUNNELED The process may be multi-threaded, but only the
>> main
>>    thread is allowed to make MPI calls.
>>
>> (and you could add
>>    If other threads make MPI calls the behavior is undefined.
>>  if you want to be verbose about it).
>>
>> -- Jim
>>
>> James Cownie <james.h.cownie_at_[hidden]>
>> SSG/DPD/PAT
>> Tel: +44 117 9071438
>>
>>
>>
>>
>> > -----Original Message-----
>> > From: mpi-21-bounces_at_[hidden] [mailto:mpi-21-bounces_at_[hidden]]
>> On
>> > Behalf Of Rolf Rabenseifner
>> > Sent: 31 January 2008 14:31
>> > To: mpi-21_at_[hidden]
>> > Subject: [mpi-21] Ballot 4 - MPI_THREAD_FUNNELED - was Re: Attending,
>> > topics, etc
>> >
>> > This is a proposal for MPI 2.1, Ballot 4.
>> >
>> > I'm asking especially
>> >   Greg Lindahl,
>> > the participants of the email-discussion in 2007, to review this
>> proposal.
>> >
>> > This is a follow up to:
>> >   Which thread is the funneled thread?
>> >   in http://www.cs.uiuc.edu/homes/wgropp/projects/parallel/MPI/mpi-
>> > errata/index.html
>> > with mail discussion in
>> >   http://www.cs.uiuc.edu/homes/wgropp/projects/parallel/MPI/mpi-
>> > errata/discuss/funneled/
>> > ___________________________________
>> >
>> > Proposal:
>> > MPI-2.0 Sect. 8.7.3, MPI_Init_thread, page 196, lines 25-26 read:
>> >
>> >   MPI_THREAD_FUNNELED The process may be multi-threaded, but only
>> >   the main thread will make MPI calls (all MPI calls are "funneled"
>> >   to the main thread).
>> >
>> > but should read:
>> >
>> >   MPI_THREAD_FUNNELED The process may be multi-threaded, but only
>> >   the main thread will make MPI calls (all MPI calls are "funneled"
>> >   to the main thread, e.g., by using the OpenMP directive "master"
>> >   in the application program).
>> > ___________________________________
>> > Rationale for this clarification from the email from Greg Lindahl:
>> >   The existing document doesn't make it clear that
>> >   the MPI user has to funnel the calls to the main thread;
>> >   it's not the job of the MPI library. I have seen multiple
>> >   MPI users confused by this issue, and when I first read
>> >   this section, I was confused by it, too.
>> > ___________________________________
>> >
>> >
>> > Best regards
>> > Rolf
>> >
>> >
>> >
>> >
>> > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner_at_[hidden]
>> > High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
>> > University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
>> > Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
>> > Nobelstr. 19, D-70550 Stuttgart, Germany . (Office: Allmandring 30)
>> > _______________________________________________
>> > mpi-21 mailing list
>> > mpi-21_at_[hidden]
>> > http://lists.cs.uiuc.edu/mailman/listinfo/mpi-21
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Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner_at_[hidden]
High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
Nobelstr. 19, D-70550 Stuttgart, Germany . (Office: Allmandring 30)