Bug 210571

Summary: DidFirstLayerFlush IPC can be head-of-line-blocked and delay first paint by 200+ ms on process swap
Product: WebKit Reporter: Ben Nham <nham>
Component: Layout and RenderingAssignee: Ben Nham <nham>
Status: RESOLVED FIXED    
Severity: Normal CC: ap, bfulgham, cdumez, ggaren, koivisto, nham, simon.fraser, thorton, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch
none
Patch
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Patch
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Patch for landing none

Description Ben Nham 2020-04-15 14:09:07 PDT 
DidFirstLayerFlush IPC can be head-of-line-blocked and delay first paint by 200+ ms on process sawp
Comment 1 Ben Nham 2020-04-15 14:14:05 PDT 
Created attachment 396571 [details]
Patch
Comment 2 Ben Nham 2020-04-15 14:14:50 PDT 
<rdar://problem/61755552>
Comment 3 Radar WebKit Bug Importer 2020-04-15 14:15:08 PDT 
<rdar://problem/61847651>
Comment 4 Ben Nham 2020-04-15 14:16:09 PDT 
Created attachment 396574 [details]
Patch
Comment 5 Geoffrey Garen 2020-04-15 14:20:00 PDT 
Comment on attachment 396574 [details]
Patch

r=me

Seems like a great way to fix this particular issue (even without adding a general priority mechanism to task scheduling). I'll wait for Tim and Simon to tell me why I'm wrong :P.
Comment 6 Ben Nham 2020-04-15 14:26:31 PDT 
Created attachment 396576 [details]
Patch
Comment 7 Ben Nham 2020-04-15 15:54:57 PDT 
Created attachment 396584 [details]
Patch for landing
Comment 8 EWS 2020-04-15 16:18:05 PDT 
Committed r260158: <https://trac.webkit.org/changeset/260158>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 396584 [details].
Comment 9 Antti Koivisto 2020-04-15 22:44:36 PDT 
Note that I have a patch in https://bugs.webkit.org/show_bug.cgi?id=208413 for general RunLoop priorities if we want to do something more generic.