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

[Richard Graham]

Why restrict this to a standard specified thread (main thread), why not word
it
 as a singe thread, and let the app decide what thread this is, based on
what
 ever criteria it wants to use to select this thread ?

Rich

On 1/31/08 10:27 AM, "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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