[Mpi-forum] MPI user survey

Jeff Squyres jsquyres at cisco.com
Mon Nov 16 12:35:50 CST 2009

Folks --

Tel me exactly what to put on the survey.  :-)

On Nov 16, 2009, at 10:11 AM, Christian Bell wrote:

> On Nov 16, 2009, at 11:55 AM, Jeff Hammond wrote:
> > 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)?"
> Why not be frank and to the point:
> The MPI Forum is currently investigating whether it is worthwhile
> supporting two RMA interfaces -- a feature-rich RMA interface and/or a
> performance-oriented interface with potentially more constraints.
> a) I only care about performance-oriented RMA
> b) I want RMA to implement a rich set of features at the cost of some
> performance/portability
> c) I think supporting 2 interfaces is a must because...
> [...]
> I won't elaborate more here because my slant against a feature-rich
> RMA will start showing (if it hasn't already).
> For the RMA folks:
> FWIW, I think a new feature-rich RMA just gives users more ways to
> write bad programs and hints at a performance benefit that
> implementations may never actually deliver.  An all-encompassing RMA
> interface is a noble goal but it doesn't seem compatible with all the
> specialization that needs to happen to exploit newer architectures.
> RMA will always be a form of specialization so it better come with a
> large carrot for users to consider it.  I'd rather have a skinny and
> constrained RMA interface that has a fighting chance to deliver what
> it aims to provide.  What's wrong with labeling a performance-oriented
> interface with "DEPRECATED: BAD IDEA" in 5 years if it will have
> failed?  IMHO, it's no worse than banking on a feature-rich RMA
> interface that may (yet again) drown in apathy.
> No disrespect is intended to those already working hard to come up
> with a complete feature-rich and performance-portable RMA, but I see
> too much pain for very little gain.
>         . . christian
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Jeff Squyres
jsquyres at cisco.com

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