From: Rolf Rabenseifner <Rabenseifner@XXXXXXXXXXXXXXXXXXXX>
Subject: MPI-2.1, 1-sided and MPI_PROC_NULL 
To: mpi-21@XXXXXXXXXXXXX
Date: Fri, 8 Mar 2002 17:27:27 +0100 (CET)
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Dick, I agree with you.
In the next batch/ballot we should add an additional sentence:
 
"After a RMA operations with rank MPI_PROC_NULL it is still necessary
to finish the RMA epoch with the synchronization method that has started 
the epoch."

Rolf 
 
 
> I am voting yes but do think there is a small remaining question regarding
> MPI_Put etc to MPI_PROC_NULL.  When using FENCE synchronization, a FENCE
> that ends an epoch may or may not begin another fenced epoch.  The
> resolution is based on the RMA operations done after it.  I.E.
> 
> MPI_Win_fence; MPI_Put; MPI_Win_fence; MPI_Put; MPI_Win_start
> 
>  is an error because the second MPI_Put has implicitly begun a fenced
> epoch and an MPI_Win_start cannot be done until the epoch which the second
> MPI_Put belongs to is fenced.  Does an MPI_Put/Get/Accumulate to
> MPI_PROC_NULL have the same side effect?  I think it must or we have made
> things more complex, not less.  The analogy to point-to-point does not give
> me a clear answer.
> 
>              Dick
> 
> 
> 
> Dick Treumann                RS/6000 SP Development
> IBM Poughkeepsie Unix Development Lab
> Dept 0lva / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
> Tele (845) 433-7846         Fax (845) 433-8363
> 
> 
> ======================================================================
> 
> 6:  Page 114, after line 4, add
> 
> MPI_PROC_NULL is a valid target rank in the MPI RMA calls
> MPI_ACCUMULATE, MPI_GET, and MPI_PUT.  The
> effect is the same as for MPI_PROC_NULL in MPI point-to-point
> communication.
> 
> ========================================================================
> 
> 
> 
> 



Dr. Rolf Rabenseifner                      High Performance Computing
Parallel Computing                         Center Stuttgart    (HLRS)
Rechenzentrum Universitaet Stuttgart (RUS) Phone:    ++49 711 6855530
Allmandring 30                             FAX:      ++49 711 6787626
D-70550 Stuttgart                   rabenseifner@XXXXXXXXXXXXXXXXXXXX
Germany                        http://www.hlrs.de/people/rabenseifner