pmix/pmix112: Enable PMIx shared memory dstore by default

[kawashima-fj]

The problem of PMIx shared memory dstore + MPI singleton is fixed now. See #2859 and #2909. We need PMIx shared memory dstore in v2.1.x.

The master branch had this change long ago and the commit includes many changes so this commit is a direct commit (no cherry-pick).

@jjhursey Please review.

Signed-off-by: KAWASHIMA Takahiro [email protected]

[jjhursey]

Thanks for this PR. This is good to go.

However, we should have a discussion in the OMPI Teleconf about if we should have this enabled by default in the 2.1.x series. I cannot remember if we decided on this yet or not. @gpaulsen Can you add this to the agenda for tomorrow.

[kawashima-fj]

@jjhursey @gpaulsen OK. I added the WIP-DNM label. Please remove it if you confirmed it.

[hppritcha]

LANL CI down for today due to NERSC quarterly maintenance.

[jsquyres]

Per 2017-02-07 webex discussion, there appears to be a bug in dstore on master. When that gets fixed and is brought over to v2.x, it seems like we want dstore to be the default on v2.x.

[hppritcha]

@hjelmn has reason to believe there is a memory corruption problem if shared memory is enabled by default.

[jjhursey]

This is the PMIx issue that @hjelmn @artpol84 are working on.

• PMIx dstore issue openpmix/openpmix#280

Once that is fixed in PMIx, then I'll update the v2.x branch with updated PMIx v1.2.1rc. We'll need those fixes in before merging this PR - so we don't break default builds.

[kawashima-fj]

bot:mellanox:retest

[hppritcha]

merge this after #2958

[jsquyres]

#2958 has been merged. Now merging this one to enable PMIx shared memory datastore by default.