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

[Michael Blocksome]

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.
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