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Subject: [OMPI devel] v1.3 RM: need a ruling
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-07-09 21:49:39


v1.3 RMs: Due to some recent work, the MCA parameter
mpi_paffinity_alone disappeared -- it was moved and renamed to be
opal_paffinity_alone. This is Bad because we have a lot of historical
precent based on the MCA param name "mpi_paffinity_alone" (FAQ, PPT
presentations, e-mails on public lists, etc.). So it needed to be
restored for v1.3. I just noticed that I hadn't opened a ticket on
this -- sorry -- I opened #1383 tonight.

For a variety of reasons described in the commit message r1383, Lenny
and I first decided that it would be best to fix this problem by the
functionality committed in r18770 (have the ability to find out where
an MCA parameter was set). This would allow us to register two MCA
params: mpi_paffinity_alone and opal_paffinity_alone, and generally do
the Right Thing (because we could then tell if a user had set a value
or whether it was a default MCA param value). This functionality will
also be useful in the openib BTL, where there is a blend of MCA
parameters and INI file parameters.

However, after doing that, it seemed like only a few more steps to
implement an overall better solution: implement "synonyms" for MCA
parameters. I.e., register the name "mpi_paffinity_alone" as a
synonym for opal_paffinity_alone. Along the way, it was trivial to
add a "deprecated" flag for MCA parameters that we no longer want to
use anymore (this deprecated flag is also useful in the OB1 PML and
openib BTL).

So to fix a problem that needed to be fixed for v1.3 (restore the MCA
parameter "mpi_paffinity_alone"), I ended up implementing new
functionality.

Can this go into v1.3, or do we need to implement some kind of
alternate fix? (I admit to not having thought through what it would
take to fix without the new MCA parameter functionality -- it might be
kinda wonky)

-- 
Jeff Squyres
Cisco Systems