RE: [AMBER-Developers] Issues with MPICH-1.2.1p1

From: Ross Walker <>
Date: Tue, 13 Apr 2010 17:07:49 -0700

> I like the "don't support MPICH-1.2.1p1" option myself as a first
> guess. I

This would be a great option is this wasn't the 'latest and greatest MPICH2
release' .AND. this same issue is likely to occur with ALL future releases
of MPICH2.

> have not looked at the code to see whether there is potential trouble
> there,
> but there are a lot of performance implications in parts of the mpi
> code...

Of course... Although I am not sure it is huge. From what I can see this
all_gatherv is only called (in pmemd at least) at the end of a GB run. E.g.
the test cases crash at step 10 of 10. That said we should probably address
it in a nice way.

> I will try to find some time to look at this further...
> (the principle I am applying here is you don't dink up your own code to
> support stuff that is broken, unless you absolutely have to...)

I agree except:

1) Convincing the MPICH2 people that they are wrong will likely be hard.
2) Having to keep telling the same thing to users again and again will be
3) These days I just want a peaceful life so I can actually do some

All the best

|\oss Walker

| Assistant Research Professor |
| San Diego Supercomputer Center |
| Tel: +1 858 822 0854 | EMail:- |
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Received on Tue Apr 13 2010 - 17:30:03 PDT
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