[Mpi-forum] MPI user survey

[Underwood, Keith D]

If we ask them if they would like to rewrite their applications, we will get a resounding no.  Again, the goal is to ask what form the new extensions should take.  We should fix RMA, but is that a minimal fix or does it include a very different interface?

Keith 

> -----Original Message-----
> From: mpi-forum-bounces at lists.mpi-forum.org [mailto:mpi-forum-
> bounces at lists.mpi-forum.org] On Behalf Of Jeff Hammond
> Sent: Monday, November 16, 2009 8:55 AM
> To: Main MPI Forum mailing list
> Subject: Re: [Mpi-forum] MPI user survey
> 
> Can we completely ignore the performance-richness dichotomy and ask
> the following?
> 
> "Would you benefit if the MPI Forum enhances and extends the existing
> one-sided operations?  That is, would you like to replace MPI
> two-sided calls in your code with one-sided ones and/or use MPI
> instead of another one-sided API (e.g. ARMCI)?"
> 
> As has been pointed out many times, this question is susceptible to
> the criticism that it is asking "should we make MPI better?" to which
> almost anyone will answer "yes", which is why it is important to query
> whether or not such improvements would actually be used in code.
> 
> Jeff
> 
> On Mon, Nov 16, 2009 at 10:43 AM, Jeff Squyres (jsquyres)
> <jsquyres at cisco.com> wrote:
> > +1
> >
> > -jms
> > Sent from my PDA. No type good.
> >
> > ________________________________
> > From: mpi-forum-bounces at lists.mpi-forum.org
> > <mpi-forum-bounces at lists.mpi-forum.org>
> > To: Main MPI Forum mailing list <mpi-forum at lists.mpi-forum.org>
> > Sent: Mon Nov 16 11:38:51 2009
> > Subject: Re: [Mpi-forum] MPI user survey
> >
> > The important thing to discern is whether we have any user base that
> wants
> > that second interface.
> >
> >
> >
> > Keith
> >
> >
> >
> > From: mpi-forum-bounces at lists.mpi-forum.org
> > [mailto:mpi-forum-bounces at lists.mpi-forum.org] On Behalf Of Vinod
> tipparaju
> > Sent: Monday, November 16, 2009 8:27 AM
> > To: mpi-forum at lists.mpi-forum.org
> > Subject: Re: [Mpi-forum] MPI user survey
> >
> >
> >
> > I am concerned with the way this question is worded.
> >
> >
> >
> > I am only concerned for a general user that is doing this survey. I
> think
> > this question seems to suggest that MPI-3 RMA will finally be defined
> in
> > such a way that either a) rich RMA feature set, or  b) good message
> rate, is
> > utimately possible. I disagree with this completely. RMA for MPI-3
> must
> > target and deliver both, even if we have to have two interfaces for
> RMA
> > (after Keith and Brian do their investigation and conclude that
> having a
> > second interface is a must). I think we cannot get away with an
> interface
> > with rich feature set that prevents high-message rate or low latency
> just
> > because 95% of users who take the survey say they only care about
> rich
> > feature set. Alternatively, if we don't care what users say and still
> are
> > going to deliver an RMA specification that gives both, why are we
> asking
> > this question?
> >
> >
> >
> > Note that I (as a participant in RMA standardization meetings)
> understand
> > that the intention of this question may be to see what people care
> more
> > about --latency/message-rate or rich feature set.
> >
> >
> >
> > I cannot see how this can be worded to address all the concerns with
> out
> > including 1/2 a page of explanation. So I think we should hold-off on
> > including this question in the survey for now.
> >
> >
> >
> > Thanks,
> >
> > Vinod.
> >
> >
> >
> > --
> > Vinod Tipparaju ^ http://ft.ornl.gov/~vinod ^ 1-865-241-1802
> >
> >
> >
> >> From: jsquyres at cisco.com
> >> To: mpi-forum at lists.mpi-forum.org
> >> Date: Mon, 16 Nov 2009 07:39:09 -0800
> >> Subject: Re: [Mpi-forum] MPI user survey
> >>
> >> On Nov 16, 2009, at 7:28 AM, Supalov, Alexander wrote:
> >>
> >> > Why don't we ask directly: do you want to have subsets in MPI-3 to
> >> > trade feature richness for performance if you care?
> >> >
> >>
> >> We didn't ask about subsets at all because the WG is "on hold". Do
> >> you want to introduce a new question? If so, can you suggest the
> >> specific wording?
> >>
> >> Note that Keith suggested an improved wording for the RMA question
> >> (this was buried in my reply to Dick):
> >>
> >> "MPI one-sided communication performance (e.g., message rate and
> >> latency) is more important to me than supporting a rich remote
> memory
> >> access (RMA) feature set (e.g., communicators, datatypes)."
> >>
> >> Jeff H. replied to me off-list that he liked this better than his
> >> suggestion. Does anyone else have any suggestions / comments on this
> >> one?
> >>
> >> --
> >> Jeff Squyres
> >> jsquyres at cisco.com
> >>
> >> _______________________________________________
> >> mpi-forum mailing list
> >> mpi-forum at lists.mpi-forum.org
> >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
> >
> > _______________________________________________
> > mpi-forum mailing list
> > mpi-forum at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-forum
> >
> >
> 
> 
> 
> --
> Jeff Hammond
> Argonne Leadership Computing Facility
> jhammond at mcs.anl.gov / (630) 252-5381
> http://www.linkedin.com/in/jeffhammond
> http://home.uchicago.edu/~jhammond/
> 
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