[Mpi-forum] MPI "Allocate receive" proposal

Rolf Rabenseifner rabenseifner at hlrs.de
Mon Aug 26 11:17:05 CDT 2013


I've three other question/comments.

1) Your last slide 7 says 

  - ARECV scenario: unexpected
    ...
    T=2: buffers unexpected message, 
         puts on unexpected list

   At this time, it is absolutely unknown, whether a 
   following MPI_(I)recv or MPI_(I)arecv will be called.

   The message may be sent with MPI_Send  / Bsend / Ssend
   (not Rsend because here scenario is "unexpected).
 
   Please, can you clarify, what may be the expected inner
   behavior for all three forms of sending and both forms
   of receiving.

2) I do not understand the datatype concept.
   There should be something like an etype
   and the MPI_Arecv(...etype...) receives a multiple
   etypes and a multiple of etypes must match 
   "count, datatype" in the MPI_Send call.
   one may use the same restrictions on this etype
   that exist for the MPI-I/O etype.

3) Small notice: you may use BASEPTR instead of buffer.
   Your MPI_Status_get_buffer(status, &buffer)
   Returns a baseptr in the same way as MPI_ALLOC_MEM.
   Your MPI_Free_mem(buffer) frees the "base".
   Please note that this baseptr/base interface is asymetric.

Best regards
Rolf

----- Original Message -----
> From: "Jeff Squyres (jsquyres)" <jsquyres at cisco.com>
> To: "MPI Forum list" <mpi-forum at lists.mpi-forum.org>
> Sent: Monday, August 26, 2013 5:10:30 PM
> Subject: [Mpi-forum] MPI "Allocate receive" proposal
> Dave Goodell and I have a proposal that we've socialized a bit around
> with other Forum members, and would now like larger Forum feedback.
> I'll be presenting the attached slides on the concept of an "allocate
> receive" in Madrid (3:30-4pm on Thursday).
> 
> There's no text or ticket yet; this is an idea that we want to get
> feedback on before working up a full proposal.
> 
> --
> Jeff Squyres
> jsquyres at cisco.com
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
> 
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-- 
Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
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: Room 1.307)



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