1665196 - Post-startup font loading causes 100ms jank

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect)

Description

[Markus Stange [:mstange]]

Profile: https://share.firefox.dev/35B3WRn

I encountered some jank while scrolling shortly after startup.

The chunk slice seems to be set to 100ms here: https://searchfox.org/mozilla-central/rev/30e70f2fe80c97bfbfcd975e68538cefd7f58b2a/gfx/thebes/gfxPlatformFontList.cpp#2106-2107

It might make sense to reduce this time and use IdleCallbacks for this work.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Is this different with gfx.font-list.shared=false?

Comment 2

[Jonathan Kew [:jfkthame]]

Is this different with gfx.font-list.shared=false?

I wouldn't expect it to be much different -- the font loader task exists in either case, and works in 100ms "chunks".

It might make sense to reduce this time and use IdleCallbacks for this work.

Yes, that seems like a potential improvement.

Comment 3

[Florian Quèze [:florian]]

I saw the same issue in a profile today: https://share.firefox.dev/3cTRnlS

Comment 4

[Jonathan Kew [:jfkthame]]

I'm experimenting with a patch to perform this work in shorter slices on the main-thread Idle queue. I'll put up a patch for review if it looks like there's a worthwhile benefit.

Comment 5

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1665196 - Use the main-thread idle queue rather than a repeating timer to finalize font loading. r=lsalzman

Comment 6

[Jonathan Kew [:jfkthame]]

Try run with the above patch: https://treeherder.mozilla.org/#/jobs?repo=try&revision=f7f83139f8755855ea574e6a4bac10211b1a3a04

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/cab81767be70
Use the main-thread idle queue rather than a repeating timer to finalize font loading. r=lsalzman

Comment 8

[Narcis Beleuzu [:NarcisB]]

Backed out for mochitest failures on test_mouse_enterleave_iframe.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/82635ef23759b44719fb391db2e785a4dab6f2ab
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=317473775&repo=autoland&lineNumber=4980

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a5e88ddf8867
Use the main-thread idle queue rather than a repeating timer to finalize font loading. r=lsalzman

Comment 10

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/a5e88ddf8867