*UI Jank Task Force Status Update*
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*Agenda*
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Excellent progress last week
- Spellchecking now in done in the renderer; moved a lot of disk access
off I/O thread.
- Launching child processes now done in background thread; off of UI / IO
threads.
- 30% improvement on Linux new tab creation histograms.
- Memory purger now available.
- First automatic purge candidate: "System memory pressure
notification"?
- Hibernate may not be the cause of thrashing. Investigation ongoing.
- Tab switching tests now live on Windows bots.
- Cookies no longer loading on startup.
New investigations
- Investigating using a flat file for safebrowsing instead of SQLite
(need to recreate bloom filter and watch disk I/O)
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*Goal review*
The team reviewed progress towards its current goals:
Measure and speed up different browser UI operations:
- First input event delta after tab switch + waking up after sleep - Have
histogram for input event delta, but don't have it for this specific 'wake'
event.
- Omnibox responsiveness - No progress.
- Tab switching when process is paged out - Added tab switching tests and
measurements.
- Whiteout duration (for the 95th percentile) --> "tab switch paint
duration"? - Have histograms for whiteout, but it's a red herring. Will
keep it around, but not as deterministic as onPaint roundtrip.
- Startup - Added child process background thread changes. Need a perf
tests for n-page session restore to prevent regressions.
- Shutdown - No progress.
- New tab creation - Background thread process creation...possibly a big
improvement on Linux.
- Tab close - May already have histograms, fast shutdown path (onUnload
handlers), but didn't measure the before & after.
Create a "Jank bot" that simulates a heavily overloaded system for running
Jank tests.
- Single core perf bots turned into 'jank bots' w/ lower memory. Also
added tab switching tests (XP interactive perf.)
No Disk I/O on UI, I/O threads.
- Added run-time check to prevent regressions.
- Moved spellchecking into renderer.
- Cookie disk I/O moved out of startup.
Choose whether to optimize PGO build for Renderer or Browser.
- PGO build working, Carlos is investigating better optimizations.
Also added many other UI Jank tweaks as well.
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