[Mpi-forum] Persistence Working Group Proposed

[Jeff Squyres]

Tony -- did this group get launched?  Cisco would be interested.

On Feb 25, 2009, at 1:17 PM, Anthony Skjellum wrote:

> Dick, there are plenty of one-end optimizations that are possible  
> though.
>
> The current technology is "half channels" and we want "whole  
> channels" too.
>
> Binding an actual channel (which I did propose in MPI-2) is also  
> possible for further optimization, and I am open to that as well.
> That makes a FIFO between sender and receiver, with single credit.
>
> I agree that a channel is desirable also.  We would make it part of  
> the discussion.  It is easy enough to specify...
>
> Tony
>
> ----- Original Message -----
> From: "Richard Treumann" <treumann at us.ibm.com>
> To: "Main MPI Forum mailing list" <mpi-forum at lists.mpi-forum.org>
> Sent: Wednesday, February 25, 2009 12:11:30 PM GMT -06:00 US/Canada  
> Central
> Subject: Re: [Mpi-forum] Persistence Working Group Proposed
>
> Tony
>
> In my opinion the lack of enthusiasm for point to point persistent  
> operations does not tell us much about the usefulness of persistent  
> operations in general. When the MPI-1 Forum decided an  
> MPI_Isend_init or MPI_Irecv_init must be a local operation and that  
> an MPI_Start of a persistent send on one side must match any form of  
> receive (persistent or not) on the other (and vice versa) most of  
> the opportunity for optimization was lost.
>
> For a persistent collective to be fully optimized, the MPI library  
> probably must be able to do collective communication at the CC_INIT  
> and return to each task a persistent request handle that is  
> irrevocably bound to all the handles created at the other tasks by  
> this collective operation. It should not be valid to create two  
> persistent BCAST requests at the root with different send buffers  
> and one persistent BCAST at the non-roots just so root could BCAST  
> from either buffer. (even if somebody thinks that would be a cool  
> bit of generality)
>
>
> Dick Treumann - MPI Team
> IBM Systems & Technology Group
> Dept X2ZA / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
> Tele (845) 433-7846 Fax (845) 433-8363
>
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>
> -- 
> Anthony Skjellum, PhD
> Professor and Chair
> Dept. of Computer and Information Sciences
> University of Alabama at Birmingham
> +1-(205)934-8657; FAX: +1- (205)934-5473
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-- 
Jeff Squyres
Cisco Systems