Bug 188787

Summary: Do not try to update the compositing policy when not in accelerated compositing mode
Product: WebKit Reporter: Carlos Garcia Campos <cgarcia>
Component: WebCore Misc.Assignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: ews-watchlist, simon.fraser, webkit-bug-importer, zalan, zan
Priority: P2 Keywords: Gtk, InRadar, Regression
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=187866
https://bugs.webkit.org/show_bug.cgi?id=188791
Attachments:
Description Flags
Patch
simon.fraser: review+, ews-watchlist: commit-queue-
Archive of layout-test-results from ews202 for win-future none

Description Carlos Garcia Campos 2018-08-21 05:23:19 PDT 
RenderLayerCompositor::updateCompositingPolicy() is called very often (called from RenderLayerCompositor::cacheAcceleratedCompositingFlags()) and it uses WTF::memoryFootprint() to decide the current compositing policy. Getting the memory footprint is an expensive operation in Linux (and I suspect other non-cocoa ports too), causing an excessive CPU usage. This caused the WPE and GTK+ unit test /webkit/WebKitWebContext/uri-scheme to start timing out in the bots, because the test expects things to happen fast and that's no longer the case. We could reduce the CPU usage a lot by not trying to update the policy when not in accelerated compositing mode. We will need a solution for the AC mode, though.
Comment 1 Carlos Garcia Campos 2018-08-21 05:25:35 PDT 
Created attachment 347631 [details]
Patch
Comment 2 EWS Watchlist 2018-08-21 19:03:20 PDT 
Comment on attachment 347631 [details]
Patch

Attachment 347631 [details] did not pass win-ews (win):
Output: https://webkit-queues.webkit.org/results/8938508

New failing tests:
http/tests/security/canvas-remote-read-remote-video-blocked-no-crossorigin.html
http/tests/security/video-poster-cross-origin-crash2.html
Comment 3 EWS Watchlist 2018-08-21 19:03:32 PDT 
Created attachment 347750 [details]
Archive of layout-test-results from ews202 for win-future

The attached test failures were seen while running run-webkit-tests on the win-ews.
Bot: ews202  Port: win-future  Platform: CYGWIN_NT-6.1-2.10.0-0.325-5-3-x86_64-64bit
Comment 4 Carlos Garcia Campos 2018-08-22 00:01:26 PDT 
Committed r235162: <https://trac.webkit.org/changeset/235162>
Comment 5 Radar WebKit Bug Importer 2018-08-22 00:03:30 PDT 
<rdar://problem/43595562>