I waffled on this issue a bit (and talked w/ Nathan about it in IM), but with my RM hat on, I'm giving a final ruling: no.
This is too "last second", and it's for an incredibly small set of platforms and configuration options. I see that the risk is pretty small for this commit, but history is littered with "but that should have worked!". I'd rather be conservative and have a good 1.6.4 release. Since this has been committed on the trunk already, we can see what happens (likely: it'll cause no problems), and someday move it over to 1.6.5 if anyone cares. - Grouchy old RM On Feb 20, 2013, at 4:51 PM, Nathan Hjelm <hje...@lanl.gov> wrote: > I talked to Pasha about the change. He suggests fragments are 2-byte aligned > to save space. I suspect that on 64-bit platforms the fragment size is > already a multiple of 8 bytes so this change will likely only affect 32-bit > systems (which is where the bus error is occurring). > > -Nathan > > On Wed, Feb 20, 2013 at 09:39:09PM +0000, Joshua Ladd wrote: >> I would hold off, if possible, until I can investigate the issue. I don't, >> off-hand, know why the 2-byte alignment, although I would suspect it's for >> performance reasons. >> >> >> Josh >> >> >> -----Original Message----- >> From: devel-boun...@open-mpi.org [mailto:devel-boun...@open-mpi.org] On >> Behalf Of Jeff Squyres (jsquyres) >> Sent: Wednesday, February 20, 2013 4:35 PM >> To: <de...@open-mpi.org> >> Subject: [OMPI devel] openib fragment alignment >> Importance: High >> >> Arrgh. I think you're going to make me eat my words >> (http://www.open-mpi.org/community/lists/devel/2013/02/12143.php). >> >> I just recently lost my access to InfiniBand test gear, so I can't test this >> myself. Hypothetically, it should be fine. But throwing in an untested >> change literally right before a release without IB vendor say-so really, >> really gives me pause... >> >> Mellanox? >> >> >> On Feb 20, 2013, at 4:27 PM, Open MPI <b...@open-mpi.org> wrote: >> >>> #3519: Move r28083 to v1.6 branch >>> -----------------------------------+-------------------------- >>> Reporter: hjelmn | Owner: hjelmn >>> Type: changeset move request | Status: new >>> Priority: major | Milestone: Open MPI 1.6 >>> Version: trunk | >>> -----------------------------------+-------------------------- >>> (In [28083]) btl/openib: don't align fragments on 2 byte boundaries >>> (changed to 8) >>> >>> cmr:v1.6,v1.7 >>> >>> -- >>> Ticket URL: <https://svn.open-mpi.org/trac/ompi/ticket/3519> >>> Open MPI <http://www.open-mpi.org/> >>> >>> _______________________________________________ >>> bugs mailing list >>> b...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/bugs >> >> >> -- >> Jeff Squyres >> jsquy...@cisco.com >> For corporate legal information go to: >> http://www.cisco.com/web/about/doing_business/legal/cri/ >> >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
