mtl/ofi: Change default provider selection behavior.

[yburette]

As more providers get added to libfabric, the default exclude list would need
to be updated.
Instead, we choose to include only the providers known to work by default.

New default:

• include: psm,psm2,gni
• exclude: none

[yburette]

This is an attempt to solve the issue reported in open-mpi/ompi-release#1169.
I have tested it on our PSM nodes and it seems to be behaving correctly.

@jsquyres @hppritcha @hjelmn Please let me know if that works for you.

[jsquyres]

Should there be another commit on here to re-raise the OFI MTL priority? I.e., if one of the "desirable" providers is included, we need a high priority for the MTL, right?

[yburette]

Well... it depends.
One can always pick the OFI MTL by using --mca mtl ofi intentionally.
But I'm not sure we want the OFI MTL with the PSM provider to have a higher priority than the PSM MTL by default at this point.

[jsquyres]

@yburette I guess I meant: restore the priority to 25 on master (which @hjelmn tells me is less than the PSM/PSM2 MTLs, but still higher than ob1).

[jsquyres]

My mistake -- I thought @hjelmn had changed the priority to 15 on master. He didn't; it's still 25. So... disregard my comments about raising the priority. 😄

[yburette]

@jsquyres I'm lost. Isn't the OFI MTL's priority already 25 on master?

[yburette]

@jsquyres Ah! Ok, no problem :-)

[ibm-ompi]

Test passed.

[yburette]

@larrystevenwise Sorry, I hadn't seen it earlier. This should also fix issue #1676

[larrystevenwise]

I can test out ompi and ompi-release when the commits hit there.

[jsquyres]

@larrystevenwise You can test PRs by checking out these git branches and trying them. The "hub" tool is useful for checking out PRs (e.g., "hub checkout #1680"). See https://github.com/github/hub.

[larrystevenwise]

Thanks @jsquyres.

I cloned and did a checkout using hub but don't see the commit. Are these the correct steps?

hub clone yburette/ompi ompi-yburette
cd ompi-yburette/
hub checkout #1680

It seems the 'hub checkout' did nothing.

[larrystevenwise]

I directly checkout out topic/fix_provider_selection with git and that works. Not sure why hub did't work. Anyway, I'll test topic/fix_provider_selection now.

[larrystevenwise]

This PR tests good for me to resolve issue #1676

[jsquyres]

Oh, github rendered my text and shortened it here to #1640. Here's what you should do:

$ git clone ...normal ompi or ompi-release repo ...
$ cd ompi (or ompi-release)
$ hub checkout https://github.com/open-mpi/ompi/pull/1680

That will do the same thing as adding a remote for @yburette's repo and checking out the specific branch.

[larrystevenwise]

Thanks jeff!

[jsquyres]

I'm going to merge this; it all looks good.