[dcmf] 32-bit ROMIO: What is the best solution?

[Rob Ross]

Hi,

We've been using the DCMF list for all sorts of things that aren't  
directly related to DCMF without any issues (as far as I know); it has  
become the successful technical communication path between IBM and ANL  
so far.

However, if you'd like to create a separate list for discussing this,  
we can do that. Is that what you would like to do? If so, can you give  
us a list of people on the IBM side that should be on the new list?  
I'd like to be done discussing where we're going to talk about this  
issue ASAP and concentrate on fixing it.

Thanks,

Rob

On Feb 28, 2008, at 11:18 AM, Michael Blocksome wrote:

>
> Unfortunately, this MPI_Aint discussion really has nothing to do  
> with DCMF.  The entrire problem and solution is with MPICH2.
>
> Is there another, less broad, mpich mailing list that we could use?   
> Maybe a "mpich-development" or something like that?
>
> Michael Blocksome
> Blue Gene Messaging Team Lead
> Advanced Systems SW Development
> blocksom at us.ibm.com
>
>
> dcmf-bounces at lists.anl-external.org wrote on 02/28/2008 11:01:09 AM:
>
> > I'd say this mailing list is better for it right now. Posting on the
> > broader mpich-discuss might just distract us.
> >
> > Rajeev
> >
> > From: dcmf-bounces at lists.anl-external.org [mailto:dcmf-
> > bounces at lists.anl-external.org] On Behalf Of Bob Cernohous
> > Sent: Wednesday, February 27, 2008 4:19 PM
> > To: dcmf at lists.anl-external.org
> > Subject: Re: [dcmf] 32-bit ROMIO: What is the best solution?
>
> >
> > bobc at us.ibm.com wrote on 02/08/2008 02:41:40 PM:
> >
> > >We all realize there are issues with MPI_Aint's in 32 bit  
> implementations.
> > >Using signed 32 bit addresses along with 64 bit offsets can  
> result in
> > >some pretty broken code.  I've reproduced several problems on
> > >BGL/BGP/linux.   The problems are most obvious with romio files >  
> 2G or
> > >virtual addresses > 2G.
> >
> > Earlier this month I posted some comments to this mailing list about
> > 32-bit MPICH/ROMIO/MPI_Aint issues (see above and the archive).
> >
> > We've started to work on the problem.   We're (optionally) making
> > MPI_Aint a 64 bit signed value even when integers/pointers are 32  
> bit
> > values.
> >
> > We'd like to start sending fix patches to the community for comment.
> >
> > However, since we are (in parallel) contributing our BGP code back
> > to MPICH and trying to converge on a common code base of 1.0.7,
> > and because this problem applies to any 32-bit platform,
> > we thought we should move the discussion to mpich-discuss to get
> > the larger community's comments.
> >
> > It's unlikely, at this point, that our patches would apply to  
> MPICH2,
> > but that is our goal after the 1.0.7/BGP patch settles.   For now,  
> we'd
> > be sending these as RFC (request for comment) patches.
> >
> > Please let us know if you agree with discussing this on mpich- 
> discuss,
> > or if there is a better place.
> >
> > Bob Cernohous:  (T/L 553) 507-253-6093
> >
> > BobC at us.ibm.com
> > IBM Rochester, Building 030-2(C335), Department 61L
> > 3605 Hwy 52 North, Rochester,  MN 55901-7829
> >
> > > Chaos reigns within.
> > > Reflect, repent, and reboot.
> > > Order shall return._______________________________________________
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