1637953 - Picture caching doesn't work on gmail

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[Jeff Muizelaar [:jrmuizel]]

When I turn on picture caching debugging and scroll gmail I get mostly red in the scroll area on my 16" MBP

Comment 1

[Bert Peers [:bpeers]]

Attachment: gmail.png

I've got nothing useful to add other than "everything is on slice 4" :\

Comment 2

[Glenn Watson [:gw]]

Confirmed locally - I'll investigate today, seems like the shape of the display list is tripping up the way slices are created.

Comment 3

[Glenn Watson [:gw]]

What seems to occur here is that WR logic is getting tripped up by the level of nesting of scroll frames.

There are three nested scroll frames. The two outer scroll frames appear to be redundant - I will investigate what causes these before working out the best way to handle such cases in the slicing logic.

Comment 4

[Glenn Watson [:gw]]

Attachment: Bug 1637953 - Fix picture caching with redundant nested scroll roots

Some pages created nesting levels of scroll roots where the outer
scroll frames are redundant (the scrollable size is zero if the
content rect is the same as the frame rect).

In these cases, it is of no benefit to select these as a scroll
root for picture cache tiles.

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Do we have a way to test this so we avoid regressions?

Comment 6

[Glenn Watson [:gw]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #5)

Do we have a way to test this so we avoid regressions?

We don't, yet - I opened a bug (https://bugzilla.mozilla.org/show_bug.cgi?id=1638198) to add infrastructure to wrench to allow us to regression test the slicing logic.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e867d81f9019
Fix picture caching with redundant nested scroll roots r=Bert,jrmuizel

Comment 8

[Cristian Brindusan [:cbrindusan]]

Backed out changeset e867d81f9019 (Bug 1637953) for wrench bustages.
https://hg.mozilla.org/integration/autoland/rev/0d9f9298b66c4ad3182f925b8aff5acf50b64637

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&selectedTaskRun=IHtl_mHqQwi6bMYxMVBzmw-0&resultStatus=success%2Cpending%2Crunning%2Ctestfailed%2Cbusted%2Cexception&revision=e867d81f901948a82da3d6294cb36ae24ffad424

Failure log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=302809282&repo=autoland&lineNumber=2836

Comment 9

[Glenn Watson [:gw]]

I had missed updating one of the wrench reftests - should be fixed now, thanks! (follow up try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=ad3e833d94600fbfd0954f84738bce859d674aaa)

Comment 10

[Glenn Watson [:gw]]

I will hold off on landing this, as it touches the exact same code as in https://bugzilla.mozilla.org/show_bug.cgi?id=1617524, and I want to ensure we get a solution that fixes both issues (I have tested locally and combining the patches seems to work fine, but I'll wait for review of the other change).

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a2078244558d
Fix picture caching with redundant nested scroll roots r=Bert,jrmuizel

Comment 12

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ff097baf211d
Backed out changeset a2078244558d as requested by :gw on slack.

Comment 13

[Glenn Watson [:gw]]

Fixed up the test failure (expected difference of one test getting subpixel, one not on Windows), and pushed a fresh try:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=21c614f28a21232048c256630007d1a59ce22657

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3afdf3a5bec4
Fix picture caching with redundant nested scroll roots r=Bert,jrmuizel

Comment 15

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/3afdf3a5bec4

Comment 16

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

== Change summary for alert #26041 (as of Fri, 22 May 2020 19:37:38 GMT) ==

Improvements:

18% tscrollx windows10-64-shippable-qr opt e10s stylo 0.88 -> 0.72
8% tscrollx linux64-shippable-qr opt e10s stylo 1.10 -> 1.01

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=26041