[Mpi-22] [MPI Forum] #71: Add routine for registering callback when finalize occurs

[William Gropp]

I checked MPICH2, and it doesn't invoke the attribute destroy  
functions in the order required here.  It wouldn't be hard to change,  
but I haven't had a chance to do that.

Bill

On Apr 2, 2009, at 3:26 PM, MPI Forum wrote:

> #71: Add routine for registering callback when finalize occurs
> ------------------------------------- 
> +--------------------------------------
> Reporter:  koziol                    |            Owner:  koziol
>    Type:  Enhancements to standard  |           Status:  assigned
> Priority:  Waiting for reviews       |        Milestone:  2009/04/06  
> Chicago
> Version:  MPI 2.2                   |       Resolution:
> Keywords:                            |   Implementation:  Waiting
> ------------------------------------- 
> +--------------------------------------
>
> Comment(by jsquyres):
>
> Other than missing a changelog, this proposal looks good (read: we  
> need a
> changelog entry ASAP before we can discuss it next week in Chicago!).
>
> Rajeev -- I think the issue with enforced ordering was inspired by
> potentially using multiple different middleware packages that may  
> not be
> able to coordinate their shutdown callbacks.  E.g., if package A uses
> package B which uses MPI, then you ''need'' to have B's finalize  
> callback
> called before A's.  A and B would be hard-pressed to coordinate this  
> if
> they didn't know about each other.  And so on.
>
> FWIW, Open MPI does ''not'' invoke COMM_SELF callbacks in any  
> particular
> order -- it'll actually be a little painful to convert to assign an  
> order
> (because we use a hash table to store this stuff).  But it's all just
> bookkeeping -- it's certainly do-able.  So someone needs to do an  
> open-
> source implementation.
>
> Bill -- did you get a chance to see if MPICH2 destroys COMM_SELF
> attributes in order?
>
> -- 
> Ticket URL: <https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/71#comment:17 
> >
> MPI Forum <https://svn.mpi-forum.org/>
> MPI Forum

William Gropp
Deputy Director for Research
Institute for Advanced Computing Applications and Technologies
Paul and Cynthia Saylor Professor of Computer Science
University of Illinois Urbana-Champaign