Performance/Snappy/2011-11-18

Responsiveness program

Need to set a simple goal

• target keyboard/mouse responsiveness
• target animation framerate

Measuring:

• Need tools for measuring slowness: gfx FPS gated on UI operations
  • automated, continuous integration
  • on-demand
  • web devs, add-on devs, fx devs, platform devs?
• should rank ui operations by importance, ie typing, mouse clicks
• the following use-cases should be instrumented with telemetry: http://j.mp/rPGyFb
• Use benoit's profiler to prioritize stacks that need fixing
• How to distribute work among various teams?
  • telemetry
  • tools

Automate:

• Use telemetry and statistics to measure progress/regression. have a list of histograms that people can check to see progress
• Have metrics do/automate trend analysis on telemetry data
• Once we have data we can try to model our performance in the field

Momentum:

• Weekly blog posts like memshrink
• Arewefastyet.com from telemetry histogram

https://etherpad.mozilla.org/responsiveness-profiling

Process:

• lots of triage
• copy memshrink queries

• visible unresponsiveness metabug: bug 698500
• sync storage main-thread-io metabug: bug 699820
• cycle collector responsiveness metabug: bug 698919

Notes mtg:

• need gfx test harness for fps: jeff taking, after thxgiving week
• dietrich coordinating telemetry for front-end actions
• goals
  • should focus on what users are complaining about
  • how to find out what's biting users? a user survey?
  • Lawrence: talk to support group?
  • probes are answers about specific areas, can't just probe the whole project
  • measure events before non-responsive code (ted's event loop lag logger)
    • doesn't cover painting
    • don't optimize for lag when browser is idle
  • taras: want a user-visible goal
  • jst: already code in place to tell when blocking user events?
    • then capture stack trace
  • measing against gmail - not static. could save a snapshot for benchmark.
  • need to find person to handle the test framework and getting infrastructure bits going.
  • get basic locally running harness so can attack directly?
• p1s
  • slow-sql telemetry
  • domstorage
    • trade off reliability for perf
    • dying api (no longer promoting it)
• mandelin: more lab-style way for devs to figure out when page X causes problem due to code Y?
  • something between telemetry and automation
  • quick feedback loo
• dump telemetry or other pause-related data into a buffer
• sql telemetry
  • distinguish main-thread vs off-thread queries
• could be useful to main thread events that take time
• are hangs part of mission here?
• out of process plugin hangs?
• startup part of this?
• android responsiveness?
• hang detector: bug 429592

Actions:

• Jeff writing gfx harness for fps
• Dietrich coordinating front-end telemetry: find owners for new tab, close tab
• Lawrence talking to support group about what users are complaining about
• Test infrastructure will be pushed on by XXX
• Nfryod looking at domwstorage, shouldn't wait on leveldb. make it less reliable, for perf
• Andrew filing bug for lab-style responsiveness log: bug 703800
• Lawrence is going to reschedule the meeting to include non-US participants