1734811 - consider to use higher priority for the imglib tasks

Status: RESOLVED FIXED

(Core :: Graphics: ImageLib, enhancement, P3)

Description

[Olli Pettay [:smaug][[e-mail]]]

Imglib uses currently mediumhigh priority, but I'd like to try to use higher than vsync priority. Initial tryserver runs hint that this could reduce some bimodality of some visual page load metrics .

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Attachment: Bug 1734811 - consider to use higher priority for the imglib tasks r=tnikkel

Depends on D127935

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Based on try this improves google slides vismet quite a bit on Fission (linux/mac), but does cause some smaller regressions elsewhere.
Non-perf tests looked ok, hopefully landing doesn't reveal any issues.
It is a bit hard to get the big picture for scheduling changes without landing and running all the perf tests and getting enough tests runs so I'm planning to try to land this and if this doesn't look good enough, backout on Monday at latest.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0532dcb4d092
consider to use higher priority for the imglib tasks r=tnikkel

Comment 4

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/0532dcb4d092

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 9244950 [details]
Bug 1734811 - consider to use higher priority for the imglib tasks r=tnikkel

Beta/Release Uplift Approval Request

• User impact if declined: Slower page loads especially with Fission
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: Bug 1734809
• Risk to taking this patch: Medium
• Why is the change risky/not risky? (and alternatives if risky): Currently imglib uses mediumhigh priority when it posts tasks to the main thread. The patch increases the priority so that images can be painted even sooner. All this is already asynchronous, so changing the scheduling a bit shouldn't be very risky.
• String changes made/needed: NA

https://treeherder.mozilla.org/perfherder/graphs?highlightAlerts=1&highlightChangelogData=1&series=mozilla-central,3422695,1,13&timerange=5184000&zoom=1633632358430,1634119928788,440.61764705882354,1197.8235294117646

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9244950 [details]
Bug 1734811 - consider to use higher priority for the imglib tasks r=tnikkel

Approved for 94.0b5.

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/3c9fd5a32e03

Comment 8

[Alexandru Ionescu (needinfo me) [:alexandrui]]

== Change summary for alert #31810 (as of Mon, 11 Oct 2021 15:08:03 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
5%	bing-search-restaurants dcf	android-hw-g5-7-0-arm7-shippable-qr	warm webrender	379.52 -> 359.12
4%	cnn-ampstories loadtime	android-hw-g5-7-0-arm7-shippable-qr	warm webrender	628.38 -> 604.50

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=31810