[Mpi-forum] MPI-3 One-Sided Communications

[Vinod tipparaju]

First, as far as my understanding goes, no, that is not why we have the active message working group.

I will not comment on if the MPI-2 missed its mark. You are more familiar with what went on that I am. In my opinion, it was a design that approached the problem of defining one-sided data access in a ubiquitous way on both CC and non-CC machines -- I wasn't participating in the forum when these choices where made.
Lower latency than two sided means many things. One of them is tag matching ( as you know very well, this can have good and bad effects based on the scenario). There are may others such as lower latency single element updates and lesser than the currently necessary synchronization for remote data access and update.
All of these have been addressed with a proposed potential solution in MPI forum RMA working group in _two_ different ways with-in the last one year. If you think neither of these two approaches have satisfied the "starting over" criterion, I would like to know, why?
Bandwidth is an entirely different story.

Vinod Tipparaju.
> To: mpi-forum at lists.mpi-forum.org
> From: tony at cis.uab.edu
> Date: Fri, 24 Apr 2009 00:32:54 +0000
> Subject: Re: [Mpi-forum] MPI-3 One-Sided Communications
> 
> Hi, I was giving my opinion...
> 
> The main requirements for one sided was achieve lower latency than two sided (as well as one sidedness), and allow for potentially lower bandwidth on long transfers as a side effect... What one sided achieved is higher latency and higher bandwidth in typical (quality) implementations.  The api is consequently a mismatch to its original purpose... It diverged from its design center.. Missed the mark... Way too complex compared to simple put and get.
> 
> Starting again from first principles with the goal of very low latency remote put and get without the legacy of existing one sided is my suggestion.
> 
> In other words : Start over.
> 
> Perhaps that is why now we have an active messages group?
> Not sure.
> 
> 
> 
> Tony
> Anthony Skjellum, PhD
> Professor and Chair
> Dept. of Computer and Information Sciences
> University of Alabama at Birmingham
> +1-205-807-4968
> 
> -----Original Message-----
> From: Vinod tipparaju <tipparajuv at hotmail.com>
> 
> Date: Thu, 23 Apr 2009 20:09:38 
> To: <mpi-forum at lists.mpi-forum.org>
> Subject: Re: [Mpi-forum] MPI-3 One-Sided Communications
> 
> 
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