[O-MPI users] Re: [Beowulf] Alternative to MPI ABI

[Greg Lindahl]

On Sun, Apr 03, 2005 at 02:19:39PM -0400, Jeff Squyres wrote:

> If so, are we therefore in agreement that a MorphMPI-like approach is a 
> good first step?

No, because we apparently disagree about what MorphMPI is. You claim
it's a lot less work than an ABI; I claim it's about the same. We
both agreed that in both cases, most of the work was building a 
C interface which is similar to the existing F77 interface. So
where's the extra work you say an ABI needs?

> Who, exactly, wants an MPI ABI?

If you look at the original presentation, the biggest win is for

1) Customers who run "canned" applications, both commercial and free
2) People who produce these apps
3) Vendors of unusual interconnect hardware.

Recall that I also said that MPI implementers have the least
motivation, because they have to do some work. For example, since
you didn't see any benefit from avoiding recompiling, it's no
surprise that you don't see anything but a negative from an ABI.

> Have there been any formal surveys conducted?

Not yet. We're at the trial balloon phase. Obviously demand has to be
proven before anyone is going to do much work on an ABI. In April I
will be attending 2 conferences with lots of people in the (1)-(3)
categories; that will give me a chance to talk to a bunch of people
who tend not to post to email lists.

-- greg