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Subject: Re: [OMPI users] [Open MPI Announce] Open MPI v1.3.3 released
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-07-22 11:20:46


On Jul 20, 2009, at 9:03 AM, Dave Love wrote:

> > Hmmm...there should be messages on both the user and devel lists
> > regarding binary compatibility at the MPI level being promised for
> > 1.3.2 and beyond.
>
> This is confusing. As I read the quotes below, recompilation is
> necessary, and the announcement has items which suggest at least
> some of
> the ABI has changed.
>

The MPI ABI has not changed since 1.3.2. We started making MPI ABI
promises with v1.3.2 -- so any version prior to that (including 1.3.0
and 1.3.1) are not guaranteed to be ABI compatible. To be clear: you
should be able to mpicc/mpif77/etc. an MPI application with Open MPI
v1.3.2 and then be able to run it against an Open MPI v1.3.3
installation (e.g., change your LD_LIBRARY_PATH to point to an OMPI
v1.3.3 installation).

Note that our internal API's are *not* guaranteed to be ABI compatible
between releases (we try hard to keep them stable between releases in
a single series, but it doesn't always work). We're only providing an
ABI guarantee for the official MPI API.

> Could the promise also specify that future ABI changes will result in
> ELF version changes to avoid any more of the mess with the 1.2 and 1.3
> libraries wrongly appearing as compatible to the dynamic linker? It
> should just be a question of managing changes and doing the right
> thing
> with libtool.
>

Yes, we should. This issue has come up before, but it's gotten
muddied by some other (uninteresting) technical issues. I'll bring it
up again with the rest of the developers.

-- 
Jeff Squyres
jsquyres_at_[hidden]