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Snappy December 13, 2012 Minutes


  • lmandel to follow up with Bas about bug 792527
    • pinged bas in the bug (the bug that Bas is working on is bug 509052)


  • Next meeting in Jan 10


Startup & Shutdown

benwa, vladan, rafael, bbondy, yoric

  • bug 818296: We no longer nuke cross compartment wrapper on shutdown. This should save 200ms+ on shutdown but our telemetry bucket prevent use from confirming this accurately :(
  • bug 810101 : Readahead for safebrowsing .sbstore files landed. ~50ms improvement on aklotz's laptop, probably even more in other environments
  • bug 818257: Investigate gradual 30% regression in startup times over the past year
  • espindola:
    • bug 815709: Shutdown time is read in the main thread.
    • With bug 815709 done, bug 814765: Include late writes in the Telemetry ping.
    • With those fixed, add support to the symbolication server for OS X and have the metrics script symbolicate the stacks.
    • Fix any late writes that show up.
    • Add a shtudown watchdog feature to the extension. Initially will only be used for shutdown to report shutdown above 30 seconds
  • aklotz: bug 815418 - telemetry on what proportion of attempted Firefox start-ups result in 'Firefox is running and not responding' - many of the same issues as bug 815709, going to try to minimize duplication of effort

Tab Strip (tab switch)

jrmuizel, bas, avi

  • bug : Finished Australis theme perf impact, found ~50% regression in tab animation FPS on slow machines. Avi looked at Australis frame paint times, confirms paint times have doubled or tripled during tab animations
  • Draft version of tab switch timing add-on available at (bug 812381) thanks to a new contributor
  • avih:
    • vlad landed bug 731974 which improves animation timing considerably and now it's mostly achieving 60 fps on slow machines.
    • Frame rates on fast machines are not indicative of animation performance.
    • Filed and working on bug 820167: Adding flush+paint processing measurements to the existing frame-rates measurement API (Start/StopFrameTimeRecording - bug 696398)
  • improve the telemetry probe being used for tab switch timing

Content (GC, CC, DOM storage, flash hang, DOM event/task scheduling)

billm, jcoppeard, smaug, mccr8, aklotz

  • bug 807021: Applied Honza's feedback on LocalStorage off the main thread. Got some performance numbers. Received a review from smaug, will land on Nightly only this week (no uplift)
  • bug 600307: Gave feedback to Honza on his total rewrite of LocalStorage. His version lands in Firefox 21
  • bug 805591: shorlander says he plans to ui-review this today! Thanks vladan and lmandel. QA in progress, still waiting for r+ from bsmedberg
  • bug 715376: Patches posted for review; bz has r+'d most of the interesting ones. Talos numbers indicate that there's minimal performance difference.

Add-on and Web page introduced slowness (add-on manager start-up)


  • Beginning to understand the code and issues
  • Feedback and discussion on bug 699839 for using async sqlite in XPIProvider
  • Add telemetry to identify particular add-ons causing slow start-up