In bug 1589796 there are some 150 minute task timeouts for windows 10 ccov mochitest-devtools:

https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=279763408&repo=mozilla-central&lineNumber=20350
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=279990182&repo=mozilla-central&lineNumber=17801
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=280118169&repo=mozilla-central&lineNumber=22256

Successful runs of chunk 16 usually run in 140+ minutes:
https://treeherder.mozilla.org/logviewer.html#?job_id=280856780&repo=mozilla-central

Other chunks run much faster -- some in as little as 30 minutes.

The problematic chunk runs only one manifest (devtools\client\webconsole\test\browser\browser.ini), so cannot be broken up further: additional chunks will not help, and changes to the scheduling algorithm will not help.

Non-ccov platforms run the problematic manifest much faster. Windows 10/debug runs the webconsole manifest in about 40 minutes.

I will increase the max-run-time to give us some breathing room, but I am very concerned: 150 minutes is a long time to wait for a task to complete, and a lot of test time in general. Also, I just increased the test time for these tasks in October (bug 1588161), when these tests were running in 120 minutes.

:nchevobbe - We could probably schedule these tests better if they weren't all in one manifest. Could devtools\client\webconsole\test\browser\browser.ini be broken into 2 or more manifests? Also, any ideas for making these run faster?
:marco - Any ideas for making these run faster on Windows ccov? How would you feel about disabling this manifest on ccov?

We have recently switched to opt builds for Linux, and we are going to switch to opt builds at some point (hopefully soon) for Windows too. This should help a lot.

Bug 1457392 is tracking the switch to opt.

https://hg.mozilla.org/mozilla-central/rev/03ca0b24c449

I can split this in multiple manifest for sure. Do we have other places where we do that? Do we have a rule of thumb on how to do such thing, how to name the files, … ?

That's great, thanks!

Sorry, I don't have much guidance. I know of some examples of multiple manifests in one directory:

https://searchfox.org/mozilla-central/source/toolkit/components/search/tests/xpcshell/searchconfigs/xpcshell-1.ini (-2, -3, -4.ini)
https://searchfox.org/mozilla-central/source/dom/webgpu/mochitest/mochitest-no-pref.ini (mochitest.ini)

but I think those have generally been motivated by other considerations.

If you can think of some logical grouping you could also move a group of tests to a new sub-directory.

Okay, I'll try to come up with something in Bug 1603765.