Snappy, March 22nd

Taras is off for a couple of weeks as he is a proud new daddy. (Congrats Taras!) In his absence, I’m bringing you this week’s Snappy update.

Last week Taras started his post with a summary of the work that went into Firefox 13. I’m pleased that Vlad has resolved the first Snappy bug for Firefox 14. (It’s a Telemetry probe but definitely a righteous change as it’s measuring slow SQL.)

Here’s a rundown of what happened in Snappy this week.

Slow SQL

As I said above, Vlad landed a Telemetry probe for slow dynamic SQL queries. He also updated about:telemetry to show the data.


The profiler saw progress this week. I hope this will continue as Benoit has a bit of time to devote to Snappy again.

  • Ehsan landed Android stackwalking support.
  • Markus Stange (mstange) has been rocking the entire UI. See the new front end screenshot. (bug 719530)
  • Front-end now using chrome and web worker. Improved the performance of operations in the UI to support a larger profile.
  • Investigated adding an option to IonMonkey to generate JIT with frame pointers on profiling builds, which will let us use our current infrastructure. (bug 736299)
  • Working towards multiple thread profiling and investigating OpenGL profiling with fence.
  • Vlad and Benoit are working to modify the SPS profiler extension to work with the Snappy Symbolication Server. (See Chromehang below.)


Updates courtesy of Vlad.

Smooth Scrolling

  • Avi has been working on fixing scrolling for OSX and Linux.
  • Avi tweaked scrolling animation to be 400ms instead of 800ms. (bug 736251 and bug 737758)


  • Mark added date controls and a selector for period of moving average.
  • Mark is working on figuring out how to detect and report changes.
  • Peptest is enabled on try. Submit your test cases (mcote can review) for changes for which you want to measure the effect on responsiveness.

Cycle Collector

  • Looking at speeding up CCs with two tabs open (Gmail+mozilla Wiki) by removing more stuff from the CC graph. Landed bugs 735342, 736763, 735550, 737060.
  • mccr8 has a preliminary patch for delaying slow CCs. (bug 710496)
  • More preliminary patches from mccr8 for removing more things from the CC graph (bug 736563, bug 737075)
  • Next will investigate CCs with 6 or so tabs open and reported slowdowns from add-ons.


Rafael identified new issues related to shutdown and has some further paths to check.

  • The switch to private browsing doesn’t close the db. (bug 735697)
  • Checking that Connection::internalClose is called on every connection we called Connection::initialize on. (bug 711076)
  • Have the basics for write poisoning working. (bug 732173)
  • Patch under review to decide if we should take the fast exit path or not. (bug 731741)

About Lawrence Mandel

Firefox program manager
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