1973251 - 10.09 - 9.2% ML Semantic History Search SHORT-SEMANTIC-pipeline-ready-latency / ML Semantic History Search SHORT-SEMANTIC-initialization-latency + 2 more (Windows) regression on Fri June 13 2025

Status: RESOLVED WONTFIX

(Firefox Build System :: Mach Core, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a mozperftest performance regression from push 810039b16c9a407cbb62b2c954f1065f1cfddfc0. As author of one of the patches included in that push, we need your help to address this regression.

Please acknowledge, and begin investigating this alert within 3 business days, or the patch(es) may be backed out in accordance with our regression policy. Our guide to handling regression bugs has information about how you can proceed with this investigation.

If you have any questions or need any help with the investigation, please reach out to [e-mail]. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
10%	ML Semantic History Search LONG-SEMANTIC-pipeline-ready-latency	windows11-64-24h2-shippable		437.00 -> 481.08
10%	ML Semantic History Search SHORT-SEMANTIC-pipeline-ready-latency	windows11-64-24h2-shippable		437.00 -> 481.08
9%	ML Semantic History Search LONG-SEMANTIC-initialization-latency	windows11-64-24h2-shippable		485.25 -> 529.92
9%	ML Semantic History Search SHORT-SEMANTIC-initialization-latency	windows11-64-24h2-shippable		485.25 -> 529.92

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask [e-mail] to do that for you.

You can run all of these tests on try with ./mach try perf --alert 45615

The following documentation link provides more information about this command.

Comment 1

[Alex Hochheiden [:ahochheiden]]

I'm taking a look now.

Comment 2

[Alex Hochheiden [:ahochheiden]]

:sparky on Matrix:

Hi Alex Hochheiden (ahochheiden) there's no impact from your patch to Firefox performance. The tests that regressed there use this HTTP server so it seems like it's related to something around that (plus all the regressions are related to latency): https://searchfox.org/mozilla-central/source/toolkit/components/ml/tests/tools/hooks_local_hub.py
You can ping :tarek in the bug to double-check with him in case there's something else that is using python in those tests.
If there isn't I'd suggest closing it as a WORKSFORME, and consider it as a harness/baseline change

So this is probably the new baseline for these tests, and my changes to the Python version aren't the cause. I'll leave it up to :tarek to decide if to close as WORKSFORME.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1966763

Comment 4

[Tarek Ziadé (:tarek)]

Thanks Alex