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rdevlin.cronin authored
Revert of Handle RenderProcessHostImpl::SetBackgrounded on Windows (patchset #4 id:60001 of https://codereview.chromium.org/926663002/) Reason for revert: This patch set re-enabled ChromeRenderProcessHostTest.Backgrounding, which is now failing on XP bots. Example logs: https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/35740/steps/browser_tests%20on%20Windows-XP-SP3/logs/ChromeRenderProcessHostTest.Backgrounding https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/35740/steps/browser_tests%20on%20Windows-XP-SP3/logs/ChromeRenderProcessHostTest.Backgrounding Original issue's description: > Handle RenderProcessHostImpl::SetBackgrounded on Windows > > This was disabled on Windows because: > > - http://crrev.com/274071 made it such that it was asynchronous via the renderer (as only > the process itself can set itself in background mode on Windows). > > - And then this was removed for Windows as part of issue 381820 as true background mode on > Windows was achieved by having the renderer itself change its process priority (which > doesn't work as the unbackgrounding request can be stuck behind other priority tasks > running in background mode). > > Also, the test for this was disabled in between (see issue 394368) -- the asynchronicity > introduced in r274071 probably causing the flakes. > > Overall there is no need to have the renderer enter PROCESS_MODE_BACKGROUND_BEGIN itself, > IDLE_PRIORITY_CLASS should be sufficient as its the same as far as CPU priority is > concerned and IO is irrelevant in the renderers. > > Thus we can get background mode for hidden renderers without running into issue 381820. > > Experiment with IDLE_PRIORITY_CLASS/BELOW_NORMAL_PRIORITY_CLASS vs the status quo. > > Watching the relevant perf bots (tab_switching.top_10 -> MPArch.RWH_TabSwitchPaintDuration) > and UMA metrics MPArch.RWH_TabSwitchPaintDuration which shouldn't regress. > And others (e.g., SessionRestore related) which will hopefully improve. > > Enable the experiment by default in the absence of Finch to get perf waterfall coverage. > > The experiment will be called "BackgroundRendererProcesses" and have 4 groups: > ["Disallow", "AllowBelowNormalFromBrowser", > "AllowIdleFromBrowser", "AllowBackgroundModeFromRenderer"] > > It will be a per-session (rather than per-profile) experiment, randomly assigning a user > to a group every new Chrome session. > > BUG=394368, 458594 > > Committed: https://crrev.com/aaf738a2cce69ce952386b48e3bc252bd307ef43 > Cr-Commit-Position: refs/heads/master@{#317042} TBR=wfh@chromium.org,jam@chromium.org,gab@chromium.org NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true BUG=394368, 458594 Review URL: https://codereview.chromium.org/940993002 Cr-Commit-Position: refs/heads/master@{#317070}
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