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Subject: Re: [OMPI devel] MPI ABI on Linux
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-09-09 09:07:24


Thanks Ralph; that helps explain things.

I did promise the ABI working group that I would ask the OMPI
community to see if anyone wanted to work with Intel on the proof of
concept. Let's put a finite end date on the CFP so that I can report
back to them: COB this Thursday, Oct 11, 2008.

Thanks.

On Sep 9, 2008, at 9:03 AM, Ralph Castain wrote:

> Just for clarification: we had a little internal discussion here
> about this topic. I fear LANL's interest in this may be somewhat
> misunderstood.
>
> Basically, a few users here have expressed that it would be
> "convenient" if they could switch MPI implementations without
> recompiling - that is our complete level of interest in this topic.
> There are no plans to request this in future procurements, no
> willingness or interest in devoting LANL resources to accomplishing
> it. We have much higher priorities than this one.
>
> If others in the community have some interest in pursuing it, they
> are welcome to do so. We are not discouraging anyone from doing so -
> just making our position on this clear so people can understand why
> we aren't stepping forward on it.
>
> Ralph
>
>
> On Sep 9, 2008, at 6:23 AM, Jeff Squyres wrote:
>
>> On Sep 9, 2008, at 2:45 AM, Ralf Wildenhues wrote:
>>
>>>> At the MPI Forum meeting in Dublin, the MPI ABI meeting was...
>>>> er...
>>>> shall we say, "spirited." :-) Both the benefits and drawbacks
>>>> of an
>>>> MPI ABI are widely contended (it's a surprisingly complex topic).
>>>
>>> it sounds quite daunting.
>>
>> It is. :-)
>>
>>>> - If it is ever completed, MPI ABI compliance will be a separate
>>>> entity
>>>> from the MPI 2.x and 3.x standards. ABI compliance will be a
>>>> checkmark
>>>> for an MPI implementation, but will be unrelated to an
>>>> implementation's
>>>> 2.1, 2.2, 3.0, ...etc. compliance.
>>>
>>> How can that be possible? An MPI ABI will have to be versioned in
>>> the same way that the API is versioned. You can have an ABI version
>>> for each API version though, I guess.
>>
>> That is correct. My first statement wasn't entirely correct --
>> "unrelated" is probably not quite the correct word. Each ABI
>> version will be tied to a specific API version. What I was trying
>> to say is that an implementation can be claim to be API compliant,
>> even if it's not ABI compliant.
>>
>>> And of course the MPI C++ ABI will require specifying a C++ ABI
>>> (which, for Windows, means specifying the compiler and possibly its
>>> major release number used), but this is venturing off into details.
>>
>>
>> Not just Windows, right?
>>
>> Ditto for Fortran.
>>
>> --
>> Jeff Squyres
>> Cisco Systems
>>
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>
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-- 
Jeff Squyres
Cisco Systems