[Mpi-22] MPI-2.2 -- change ABI or not?

Richard Treumann treumann at [hidden]
Mon Apr 6 07:15:38 CDT 2009

Changing the ABI strikes me as a disaster.  ( I did not notice this
discussion until just now )

If anyone is thinking it is OK for the Forum to cause a 2.1  application
compiled against MPI 2.1 headers to fail on an MPI 2.2 version of the same
implementation or the reverse (2.1 application compiled with 2.2 headers
fails on a 2.1 implementation) then I need to hear a really good reason.
And I mean really, awesomely, spectacularly, bodacious ) good.

The user of a parallel application does not always have control over the
level of MPI installed on the systems he uses and does not always have the
source code to recompile. Some people use multiple systems (same
architecture but maybe different MPI version)

 It seems like a very bad idea to tell the user of MPI that he must upgrade
all MPI software he uses on the same day the system admin installs the MPI
2.2 version of the MPI implementation.

It seems like an equally bad idea to be telling system admins they are
forbidden to upgrade to the MPI 2.2 version because one of more critical
applications used on the system cannot be easily rebuilt in MPI 2.2
compatible form.

If a shop uses only one ISV application then perhaps they can use the MPI
level the ISV specifies but what does a shop that uses assorted ISV
applications do if some vendors stick with MPI 2.1 headers and others
compile for 2.2?


Dick Treumann  -  MPI Team
IBM Systems & Technology Group
Dept X2ZA / MS P963 -- 2455 South Road -- Poughkeepsie, NY 12601
Tele (845) 433-7846         Fax (845) 433-8363

mpi-22-bounces_at_[hidden] wrote on 04/04/2009 12:20:59 PM:

> [image removed]
> [Mpi-22] MPI-2.2 -- change ABI or not?
> Jeff Squyres
> to:
> MPI 2.2
> 04/04/2009 12:25 PM
> Sent by:
> mpi-22-bounces_at_[hidden]
> Please respond to "MPI 2.2"
> On Apr 4, 2009, at 9:53 AM, Jeff Squyres (jsquyres) wrote:
> > But the general point may need broad discussion next week -- have we
> > been sure to adhere to the "must be ABI compatible" rule for all
> > MPI-2.2 issues?
> >
> (changed the subjet to be more accurate)
> I notice that ticket #5 has already had a 1st reading; it will
> certainly change the ABI.
> My point: if we are taking a hard line to make it possible for any
> existing MPI-2.1 application to be able to run against MPI-2.1 and
> MPI-2.2 versions of the same implementation, we will need to review
> all MPI-2.2 tickets.
> --
> Jeff Squyres
> Cisco Systems
> _______________________________________________
> mpi-22 mailing list
> mpi-22_at_[hidden]
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-22

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