Firefox Startup Performance Weekly Summary

No numbers summary this week, as 1) there weren’t any major landings and 2) I’m working on a script to automate the generation of these summarized numbers. Updates on the week’s activity is below. As usual, more details and links are available on the project wiki, and we’re available to answer questions in #startup on irc.mozilla.org.

• Taras and Joel are working on bug 524202, tracking down exactly how and when dynamic library code is loaded. See this comment for a good summary of the issue.
• I think I’ve found a scenario for stable cold startup numbers on Windows, which is basically: 1) Run consume.exe for N seconds where N is how long it takes to consume all physical RAM (and which also pegs the CPU), 2) sleep for 30 seconds (or however long it takes for the system to quiet down) and 3) measure startup time as usual. Next step is to get a Talos patch up, and work with Rel/Eng to get it deployed into testing so we can see numbers on real Talos boxes.
• Rob Strong split up the update service in bug 311965, has most reviews (affects all toolkit apps) and is about ready to land. This showed a significant win on WinCE startup.

Projects in a holding pattern:

• Drew has a patch up for bug 506814, getting rid of Change GetPersistentDescriptor/SetPersistentDescriptor on Mac, just needs review from Josh.
• Bug 512645, removing the setTimeout 10ms wait in chrome JS, is just waiting on review just needs to be landed (thanks jesse).
• Ben Hsieh has been prototyping a whole Fastload cache replacement in bug 520309.
• Ted has been looking at re-enabling rebasing on Windows in bug 484799 for a potential performance boost there.
• Service caching work in bug 516085 still needs to be pushed to the Places branch for testing.
• Moving font-loading out of the startup path on Mac: Jonathan Kew filed bug 519445 with a WIP patch for yet further reductions in Mac startup time spent in font system initialization.
• JARification: David abandoned moving JS modules into a JAR file, since those files are fastloaded. However, since we want things like post-extension-install restarts to be fast, and those cause fastload cache invalidation, we might want to do things like this anyways. I filed a bug for the same treatment for components. These are lower priority, since they’re not the normal startup case. Follow along with all JAR-ification via the tracker bug.
• Startup Timeline: No updates, still not landed. Add [ft] in the whiteboard of your bug w/ the function names you want timed and David will generate it and update the bug.
• Static Analysis: No progress on bug 506128. David needs to file a bug with the final log of named-yet-uncalled functions.
• Dirty Profile Testing: No progress. Need to list scenarios, file bugs for each, generate Talos config patches and profile data, and then move it into Rel-Eng territory. Also, need to get a separate Tinderbox tree, since it’s going to cause a bazillion new columns.
• Joel Reymont noted in bug 513076 that there are serious drawbacks to getting our libraries in the dyld shared cache on Mac, so has deprioritized that work.
• No updates on Zack’s CSS parser changes in bug 513149.

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