1988181 - Avoid limiting xpcshell tests to 4 cores on Android emulators

Status: RESOLVED FIXED

(Testing :: XPCShell Harness, task)

Description

[Florian Quèze [:florian]]

Our xpcshell tests currently run on 4 cores on our Android xpcshell jobs, even though the workers have 8 logical cores.

There's a limit to 4 parallel tests at https://searchfox.org/firefox-main/rev/3de2d8eb788da636e08c85dbb7b453857d181e87/testing/xpcshell/remotexpcshelltests.py#389
Then the same file also limits to 10 parallel tests at https://searchfox.org/firefox-main/rev/3de2d8eb788da636e08c85dbb7b453857d181e87/testing/xpcshell/remotexpcshelltests.py#777-779

Because that's clearly not enough, there's also a --threads=4 at https://searchfox.org/firefox-main/rev/3de2d8eb788da636e08c85dbb7b453857d181e87/testing/mozharness/configs/android/android_common.py#282
Removing that parameter entirely makes tests fail with a "TEST-UNEXPECTED-FAIL | remotexpcshelltests.py | no more free processes" error message that I haven't debugged. I think changing that to --threads=10 to match the other limit set in remotexpcshelltests.py is reasonable.

After changing all of that, the CPU use in our test workers goes from 50% to 60%. At that point, I realized we also limit the core counts when starting the android emulator (there are -cores 4 command line parameters). Changing these to -cores 8 gives me CPU use between 95 and 100% in the test worker.

Comment 1

[Florian Quèze [:florian]]

Attachment: Bug 1988181 - Avoid limiting xpcshell tests to 4 cores on Android emulators, r=jmaher.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/2666cc71fe41
https://hg.mozilla.org/integration/autoland/rev/5e9479d3dd1e
Avoid limiting xpcshell tests to 4 cores on Android emulators, r=jmaher.

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/5e9479d3dd1e