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Subject: Re: [OMPI devel] MPI ABI on Linux
From: Ralf Wildenhues (Ralf.Wildenhues_at_[hidden])
Date: 2008-09-09 12:14:55


* Jeff Squyres wrote on Tue, Sep 09, 2008 at 03:07:24PM CEST:
>> On Sep 9, 2008, at 6:23 AM, Jeff Squyres wrote:
>>> On Sep 9, 2008, at 2:45 AM, Ralf Wildenhues wrote:
>>>
>>>> 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.

Agreed.

>>>> 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?

No, but at least on some other systems there is no confusion about which
C++ ABI to pick.

>>> Ditto for Fortran.

Of course. The devil is in the details.

> 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.

I'm sure you must mean September not October there.

Are things like timeouts, latencies, and small-message sizes intended
as part of the ABI as well? IOW, is it expected to be possible to run
one process compiled with OpenMPI and one process with MPICH, and have
them communicate with each other?

Cheers,
Ralf, ready be told that I have no idea what I'm talking about ;-)