1961153 - 4.9 - 4.15% vpl-h264 posterEnd / vpl-h264 secondFrame + 2 more (Android) regression on Thu April 10 2025

Status: RESOLVED WONTFIX

(Core :: Graphics: WebRender, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push d2b3b97ca207c65973c3020912a671de031354a9. 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)	Performance Profiles
5%	vpl-h264 estimatedFirstFrameLatency	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	524.69 -> 550.41	Before/After
5%	vpl-h264 firstFrame	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	524.69 -> 550.41	Before/After
5%	vpl-h264 posterEnd	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	524.69 -> 550.41	Before/After
4%	vpl-h264 secondFrame	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	560.08 -> 583.31	Before/After

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 44731

The following documentation link provides more information about this command.

Comment 1

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

Set release status flags based on info from the regressing bug 1958109

Comment 2

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

It has been over 7 days with no activity on this performance regression.

:gw, since you are the author of the regressor, bug 1958109, which triggered this performance alert, could you please provide a progress update?

If this regression is something that fixes a bug, changes the baseline of the regression metrics, or otherwise will not be fixed, please consider closing it as WONTFIX. See this documentation for more information on how to handle regressions.

For additional information/help, please needinfo the performance sheriff who filed this alert (they can be found in comment #0), or reach out in #perftest, or #perfsheriffs on Element.

For more information, please visit BugBot documentation.

Comment 3

[Glenn Watson [:gw]]

I've been on PTO which for the last week, but looking at this - it appears to be an expected (and unavoidable) regression. The patch in question introduces a new shader variant (for compositing with a rounded corner rect) which gets compiled once on startup. After that first shader compilation it will be cached on disk for subsequent startups (on platforms that support shader caching, which includes most android devices). However, this will show up in CI since the cache won't exist during each run. I will do some profiling this week to verify this hypothesis before I close as WONTFIX.

Comment 4

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

Set release status flags based on info from the regressing bug 1958109

Comment 5

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

The severity field is not set for this bug.
:gw, could you have a look please?

For more information, please visit BugBot documentation.

Comment 6

[Glenn Watson [:gw]]

Confirmed that the detail in comment 3 is correct.