Quantum Flow Engineering Newsletter #13

I’m back with some more updates on another week worth of work on improving various performance aspects of Firefox.

Similar to the past weeks, Speedometer remains a big focus area for performance work.  In addition to the many already identified bugs to work on, we are also still measuring the benchmark quite actively looking for more optimization opportunities.

Another item worthy of an update is Background Hang Reports.  Michael Layzell earlier today enabled collection of native stack traces on Win64 (and Mac) using the Gecko Profiler stack walking backend (Linux support soon to follow).  Because we are now using the Gecko Profiler backend for BHR, we can soon get interleaved native and pseudo-stacks from BHR similar to the ones that we have come to know and love in Gecko Profiler for a long time now!  Also, Doug Thayer has made a lot of progress on hangs.html, his front-end for exploring the native stack traces uploaded from BHR.  This is a nice and super fast tool to explore the hangs that our users are experiencing on the Nightly channel and it shows you the corresponding pseudo-stacks that are extremely helpful if for example the hang is coming from chrome-privileged JS (where we get full call stack information through telemetry).  Please have a look, and send him feedback.

This edition is exceptionally short, but the most interesting part of these is probably the last part anyway, the credits section, where I acknowledge the hard work of the people who worked on improving the performance of Firefox in the past week.  So let’s get to that, and I do hope I’m not dropping any names:

Tagged with: , ,
3 comments on “Quantum Flow Engineering Newsletter #13
  1. bull500 says:


    Thank you for your+team efforts with Quantum! Love seeing the improvements coming in Nightly

    There’s an old bug which kinda of relates to UI performance; not sure if it would come under Quantum.
    The initial bug is marked “resolved” but the sub-bugs are still in limbo and hence the core issue is still visible on the test site.
    If fixed it could lead to a boost in visual transformations for slide-out HTML menus.

    Here was the original bug – https://bugzilla.mozilla.org/show_bug.cgi?id=1141468
    It contains all the details as well.

    • ehsan says:

      Hmm, I don’t know much about that bug. But if there are unresolved issues from that bug still left unfixed, you may want to file a new bug for it, preferably with a test case if possible, to make sure it gets the attention it deserves. The right people are very unlikely to be reading this blog, but they will be reading bugzilla. 🙂