Bug 220759

Summary: REGRESSION (r271508) Scrolling is no longer smooth
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: ScrollingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: cmarcelo, darin, ews-watchlist, fred.wang, jamesr, luiz, sam, simon.fraser, tonikitoo, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=220635
Attachments:
Description Flags
Patch none

Description Simon Fraser (smfr) 2021-01-19 18:41:01 PST
REGRESSION (r271508) Scrolling is no longer smooth
Comment 1 Simon Fraser (smfr) 2021-01-19 18:41:58 PST
Created attachment 417936 [details]
Patch
Comment 2 Darin Adler 2021-01-19 19:08:15 PST
Comment on attachment 417936 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=417936&action=review

> Source/WebCore/ChangeLog:9
> +        r271508 has a logic error that resulted in no scrolling thread layer commits, which meant that
> +        scrolling on pages with a busy main thread only updated layers at main thread cadence.

Is a regression test possible?
Comment 3 Simon Fraser (smfr) 2021-01-19 21:07:23 PST
I'd have to write a bunch of infrastructure to test this (count layer commits on the scrolling thread).
Comment 4 EWS 2021-01-19 21:23:12 PST
Committed r271637: <https://trac.webkit.org/changeset/271637>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 417936 [details].
Comment 5 Radar WebKit Bug Importer 2021-01-19 21:24:14 PST
<rdar://problem/73388312>