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-- Dick Treumann IBM RS/6000 Division (Internet) treumann@pok.ibm.com Poughkeepsie, NY (VNET) TREUMANN at KGNVMC Tel: (914) 433-7846 (internal) treumann@windsurf.pok.ibm.com Fax: (914) 433-8363--------------446B794B15FB Content-Type: message/rfc822 Content-Transfer-Encoding: 7bit Content-Disposition: inline
Message-ID: <338DD53D.167E@pok.ibm.com> Date: Thu, 29 May 1997 15:13:01 -0400 From: Dick Treumann <treumann@pok.ibm.com> Organization: IBM Power Parallel Systems - RS6000 Division X-Mailer: Mozilla 3.01 (X11; U; AIX 1) MIME-Version: 1.0 To: Bill Saphir <wcs@saphir.org> CC: treumann@minnie.nic.kingston.ibm.com, salo@sgi.com, wcs@nersc.gov Subject: Re: comments on first 80 pages References: <199705270439.VAA00318@saphir.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit
Bill Saphir wrote: > > > 63:3-4 Since MPI states that interaction between MPI and non-MPI > > modes of interprocess communication is undefined, can we > > imply that MPI_COMM_JOIN is OK between processes which > > share a MPI_COMM_WORLD or MPI parent/child relationship? > > I think this should say: The processes must not have a > > preexisting MPI connection. > > This was discussed when we were designing the function. I don't > remember exactly why, but the intent was that *any* MPI processes > could use it, even if they already had an MPI connection.
Do you mean this was discussed in the open Forum or only in the Dynamic subcommittee? I do not remember the discussion or the reasoning.
> Also, I don't think the fact that the interaction of MPI and > non-MPI communication is undefined has any bearing here. Are > you thinking of anything specific? > To me it seems clear that the establishment of a SOCK_STREAM socket involves communication which is not MPI communication. Also, the communication hidden under the MPI_JOIN call is arguably NOT MPI communication. (no communicator, no context). To my mind, MPI_Join's legitimacy is quite closely tied to a requirement that there not be concurrent MPI communication linking the processes involved. If it is legal for tasks A and B to be members of some communicator and to have outstanding MPI communications on that communicator at the moment they decide to construct a socket connection and do an MPI_Join through it then you have accepted the responsibility to define the interation between socket communication and MPI communication (including impacts on the MPI progress rule).
Dick
-- Dick Treumann IBM RS/6000 Division (Internet) treumann@pok.ibm.com Poughkeepsie, NY (VNET) TREUMANN at KGNVMC Tel: (914) 433-7846 (internal) treumann@windsurf.pok.ibm.com Fax: (914) 433-8363--------------446B794B15FB--