MailNews:Performance Testing:Meeting 2008 01 09

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Discussion with Alice from MoCo on 2009/01/08 (Standard8, bienvenu, gozer, asuth present):


Firefox's development of performance tests was initially quite ad-hoc. Tried to do too much at once and this delayed getting any numbers out.

Suggestions for setting up

  • Start small, probably time to startup
    • Firefox have found this a useful number and its caught some regressions
  • Get one test running first, get confidence in the test platform and stability before trying others.

Test Machines

Firefox have set these up to get the minimum variance possible. To do this requires work, but makes checking for regressions much easier.

  • Dedicated boxes.
    • Should be isolated from the network as possible (to avoid network lags/interference)
    • Physical boxes are require, synchronisation problems in Virtual Machines cause skews in the numbers.
  • Suite of test machines.
    • Firefox have 3 machines per platform.
      • Gives redundancy if one machine gets its figures wrong.
      • Very important choice - helps to get developers to trust the numbers.
  • To avoid number drift:
    • Reboot machines after each test run. There is a buildbot set that can do this.
    • This also helps to reduce the variant in the numbers.
  • Machines, directories etc to be as clean as possible:
    • Check screen resolution
    • Must be nit-picky
    • Talos reference images are very reduced - minimum apps, items switched off.
    • Sometimes it is easier to wipe a box and reinstall if it is playing up rather than investigate the problems.

Performance Architecture

  • Suggested that Talos is used/extended:
    • Can interact with the graph server
    • Can monitor CPU usage & memory of processes
    • Has recently been extended for Fennec, so some of the Firefox-specific code has already been removed.
    • Can log results locally.

Talos bugs go under Engineering: Talos.

Graph Server

  • sqlite database
  • Currently undergoing redesign, should be finished Jan/Feb.

Graph Server bugs go under Web Tools/Graph Server.

Time to Startup

  • Measured 20 times in a row, average median taken.
  • TB could do different profile sizes, e.g. "install", "lightweight", "medium", "heavyweight".