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Subject: Re: [OMPI users] Upgrade from Open MPI 1.2 to 1.3
From: Serge (skhan_at_[hidden])
Date: 2009-04-27 14:04:23


Hi Jeff,

> That being said, we have fixed this issue and expect to support binary
> compatibility between Open MPI releases starting with v1.3.2 (v1.3.1

As far as I can tell from reading the release notes for v1.3.2, the
binary compatibility has not been announced yet. It was rather a bug fix
release. Is it correct? Does it mean that the compatibility feature is
pushed to later releases, v1.3.3, 1.3.4?

In my original message (see below) I was looking for advice as for a
seamless transition from v1.2.x to v1.3.x in a shared multi-user
environment.

Interestingly enough, recently I noticed that although it's impossible
to run an application compiled with v1.2.x under v1.3.x, the opposite
does actually work. An application compiled with v1.3.x runs using Open
MPI v1.2.x. Specifically, I tested an application compiled with v1.3.0
and v1.3.2, running under Open MPI v1.2.7.

This gives me a perfect opportunity to recompile all the parallel
applications with v1.3.x, transparently to users; and then switch the
default Open MPI library from v1.2.7 to v1.3.x, when all the apps have
been rebuilt.

The problem is that I am not 100% sure in this approach, even having
some successful tests done.

Is it safe to run an application built with 1.3.x under 1.2.x? Does it
make sense to you?

= Serge

Jeff Squyres wrote:
> Unfortunately, binary compatibility between Open MPI release versions
> has never been guaranteed (even between subreleases).
>
> That being said, we have fixed this issue and expect to support binary
> compatibility between Open MPI releases starting with v1.3.2 (v1.3.1
> should be released soon; we're aiming for v1.3.2 towards the beginning
> of next month).
>
>
>
> On Mar 10, 2009, at 11:59 AM, Serge wrote:
>
>> Hello,
>>
>> We have a number of applications built with Open MPI 1.2 in a shared
>> multi-user environment. The Open MPI library upgrade has been always
>> transparent and painless within the v1.2 branch. Now we would like to
>> switch to Open MPI 1.3 as seamlessly. However, an application built with
>> ompi v1.2 will not run with the 1.3 library; the typical error messages
>> are given below. Apparently, the type ompi_communicator_t has changed.
>>
>> Symbol `ompi_mpi_comm_null' has different size in shared object,
>> consider re-linking
>> Symbol `ompi_mpi_comm_world' has different size in shared object,
>> consider re-linking
>>
>> Do I have to rebuild all the applications with Open MPI 1.3?
>>
>> Is there a better way to do a smooth upgrade?
>>
>> Thank you.
>>
>> = Serge