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Many Projects, all Complementary

  • MozBase
  • Special Powers
  • Going Faster


Special Powers

  • API Implemented in Mochitest
  • Needed in Reftest, Mozmill
  • Needed in XPCShell?
  • Porting Mochitests to API
  • Will have some performance impact
  • Goal: Enable test harnesses to run in out of process architecture and still have access to chrome privileges/APIs as required


  • Goal: Reducing the end to end time as measured from pushing a change to getting results.
  • Early Profiling results
    • packed.js seems to average about 110ms per load.
    • There are around 3100 test files in mochitest. So, eliminating packed.js would save almost 341 seconds (5 minutes) per run.
    • In the makeIframe script, I'm seeing the window.scrollTo call take 8-10ms per call. Not sure how much we can streamline that, but best case that's 24 seconds on every run.

Related to GoFaster and MozBase

  • httpd.js could be a bottleneck.
  • How to profile?
  • How to go about trying out replacements to it?
  • Even if we stay with httpd.js, we need a better story for packaging it so that you download one item and it "just works" (tm)

Discussion Points

  • How to best work together without stepping on toes?
  • How can we monitor test harness performance so we know if we check in something that blows our gains?

Meeting Notes

Special powers

  • Cleanup harness
    • Many tools touched (unit tests, talos etc.)
  • Moving tests to the right harnesses
  • Update all the tests
    • need to contact other devs to fix their tests
  • Mochitest monitoring to see if Special Powers will slow us down, need to check end to end time

Going Faster

  • Getting rid of packed.js would shave ~5 mins from test run of mochitests. We only use a small bit of it, we don't need to load all.
  • Write a Mochitest profiling test suite so we can run to profile our progress.
  • Is our JS webserver a bottleneck? Should we switch to another server? Suggestions: nginx, lighttpd, etc.
    • Profiling: Run a suite that doesn't use .sjs or special content headers and test against current httpd.js server and the server we're testing
  • There should be profilers for each harness, but start with mochitests.
  • Should we combine some Mochitest test files into one huge generated test instead of a directory of many test files so we can load the overhead once?