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

[Michael Blocksome]

Also, the IBM-ANL collaboration won't be limited to the MPI_Aint issue. We 
plan on contributing patches to the mpich community regularly now that the 
dcmf software is open source.  Discussion of those (future) patches would 
best fit a "mpich-development" type of mailing list.

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 11:18:26 AM:

> 
> 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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> > dcmf at lists.anl-external.org
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> > http://dcmf.anl-external.org/wiki
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