For various reasons, the European meetings are at times I find it very
hard to attend, but here is a very high-level comment from someone who
teaches and advises on MPI, program design / software engineering etc.
Something that I would make a plea for is less featuritis - in particular,
most MPI users are NOT among the communities that want even most of MPI 2.
Before I wrote my course, I did a survey of all of the scientific programs
I could get my hands on, and they used a very small subset of MPI 1 with
merely a couple of MPI 2 features. If anyone would like the (now rather
dated, but sporadically updated) data, please ask.
Quite a lot of users have expressed the desire for safely portable and
simple subset - which is roughly what I teach, though it's obviously an
artificial boundary. But it would help a lot when producing interfaces
to other languages, ports to fairly different systems and so on, as well
as with learning MPI and teaching it.
So not everybody wants more and more - and it's NOT true that we can
simply ignore what we don't use - though MPI does pretty well in enabling
that. All I request is that people bear this in mind.