The default value for running on Swarming for Mac is 10.9 - see https://cs.chromium.org/chromium/build/scripts/slave/recipe_modules/swarming/api.py?q=swarming/api.py&dr&l=378

I suggest that we flip the default to 10.12 when we are happy with the 10.12 pool.

Very exciting? Who would be an appropriate owner for looking into the 10.12 pool?

Not sure - I think Dirk should take ownership and figure out who is the correct person to push this forward.

We don't have the capacity in the pools to move all of the jobs over in one go, and it would probably be too risky to do so regardless.

Currently, mac_chromium_rel_ng is configured to mirror the Mac10.9 Tests bot, and we'd want that bot to keep running tests on 10.9, so we can't mess with its configuration.

[As an aside, tansell@ is correct that the default OS for swarming on Mac is 10.9, but the Mac10.9 Tests bot actually explicitly sets that:

https://cs.chromium.org/chromium/build/scripts/slave/recipe_modules/chromium_tests/chromium_mac.py?l=54

].

So, what we need to do is set up a "dummy" builder so that we can change the mac_chromium_rel_ng configuration without affecting the 10.9 Tests bot. You could do so by creating another entry in the chromium_mac.py file linked above (called, e.g., "Dummy Mac Migration Test Builder" and then change the entry in trybots.py:

https://cs.chromium.org/chromium/build/scripts/slave/recipe_modules/chromium_tests/trybots.py?l=453

Once you did that, I'd expect the path forward to be:

1) land a CL to move a couple of targets over manually by changing the entries in chromium.mac.json to specify the dimension explicitly.
2) double-check to make sure things are stable and we have capacity.
3) check to see if we can now shift some capacity from 10.9 to 10.12 and file a ticket w/ labs to do so.

Repeat until done.

Unfortunately, I'm not sure if we have people in the Ops team who have the cycles to do this work at the moment. I can ask around, but given that this stuff is pretty straightforward, maybe a mac dev would be willing to help out? erikchen@, bouncing this to you for your thoughts (feel free to bounce back).

Note that the mac_chromium_rel_ng is *already* running some tests on 10.12 as I mentioned above.

The following tests are already running on 10.12;
 
 * WebKit Layout Tests (when run on Swarming)
 * Some GPU tests like '[trigger] depth_capture_tests on Intel GPU on Mac (with patch) on Mac-10.12'. These are triggered with "Run on OS: 'Mac-10.12'"

It feels a little wrong that some of the tests are running on 10.9 and some on 10.12 on the same builder?

Yes, definitely is is wrong that we're running some on 10.9 and some on 10.12. They should all be on one or the other, but that's what you get from being in the middle of the migration.

Unless I'm missing some point from your comment?

My confusion was that you were saying we didn't have the people to do the migration -> I assumed that nobody was doing the migration -> we hadn't started the migration -> hence 10.12 bots were weird.

You'll recall that we had the debate as to whether to run the layout tests on 10.9 vs. 10.12, and concluded that we couldn't easily deploy additional 10.9 capacity.

There is also the GPU tests, but those are indeed just weird :).

I believe this is actually done now.

Awesome, given that I didn't do anything...assigned the Fixed bug to tansell to accurately reflect the owner.

Oh, you might want to check that non-LayoutTests have moved to Mac10.12

Superceded by Issue 805475.