Firefox/Projects/Startup Time Improvements

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Overview

Sprint lead: Dietrich
Sprinters: Ryan, Drew, David

Description
Investigate areas for Ts wins, find & fix issues that help Fennec and WinCE

Goals / Use Cases

  • The core goal of this sprint is to achieve visibility into the performance-related problem areas during browser startup, and to use that visibility to create actionable bugs, creating a clear development path to move forward on.
  • The secondary goal is to fix bugs in which a resolution path is already clear, and that would provide a human-noticeable win in Fennec or WinCe.
Non Goals
Fix all the identified areas. Should ensure that the relevant people are aware of bugs filed, and work to get the bugs with potentially big wins prioritized.

Plan

  • Create a baseline profile for testing
  • Create and document measurement tools and strategies
  • Identify code paths that take the most time at startup
  • File bugs for problems found to be actionable

Tasks

  • Define the test environment
    • Create a baseline profile to measure startup against (Dietrich)
    • Prefs, platform-specific issues
  • Create an easily accessible timeline of the startup path (David)
      • STATUS (2009-07-21): Compiling and linking. We needed to use NS_COM instead of NS_EXPORT. (I would like to know why/how/etc.)
      • HOW TO USE THIS PATCH: [1]
      • Split the patch up into 3 patches for easier review: CPP, JS and Instrumentation
  • Mine the Ts DTrace visualization for opportunities (Drew)
    • bug 504858 - Investigate delaying initialization of bookmarks toolbar
    • bug 504872 - Investigate further delaying initialization of the search bar
    • See DTrace links below also
  • Log and mine filesystem operations during startup (Ryan)
  • Mine bugzilla for existing startup bugs and tag them (Dietrich)
  • Hot vs. cold testing
    • Running with fastload crippled/disabled

References

Meta-bugs and Searches

Needs investigation

Previous work

Tips, Tools

Fastload

Measuring Ts

  • starup-unix.pl in mozilla/tools/performance/startup
    • edit it to use http://pastebin.mozilla.org/663935 in place of startup-test.html
    • set dom.allow_scripts_to_close_windows and browser.dom.window.dump.enabled to true in your testing profile
    • run it in a loop to collect more stable results:
#!/bin/bash
cd ~/moz/trunk/mozilla/tools/performance/startup
for ((i=0; i < 5; i++)) do perl startup-unix.pl ~/moz/trunk/build-dbg/dist/MinefieldDebug.app/Contents/MacOS/firefox-bin -P startup >> results.txt; done;

Scratchpad

  • convert browser/utils.js to a module, memoized getter in the overlay
  • have any bookmark/history observers be category observers
  • lazy load DownloadUtils.jsm in browser.js (global memoized getter array for imports?)
  • memoized getter for PluralForm.jsm inside DownloadUtils.jsm
  • #define out all the LOG functions
  • nsiupdate check - if wince, always have write access, so don't need checks
    • n810?
  • consolidate the zillion redundant getService calls in browser.js
  • shortcut newURI(str) in browser.js
  • does FeedWriter need to be a component? (see bug 336903)
  • remove the inclusion of debug.js from everywhere
  • remove all the log() functions (or move it to debug.js)
  • globalOverlay.js:isValidLeftClick has no callers
  • globalOverlay.js:FillInTooltip's only caller is http://mxr.mozilla.org/mozilla-central/source/toolkit/obsolete/content/globalOverlay.xul
  • globalOverlay.js:goOnEvent has no callers
  • unused: http://mxr.mozilla.org/mozilla-central/source/toolkit/obsolete/content/globalOverlay.xul
  • globalOverlay.js:visitlink() only used in credits.xhtml
  • globalOverlay.js:goSetAccessKey() has no callers
  • globalOverlay.js:goSetMenuValue() has no callers
  • can globalOverlay.js be removed altogether?
  • run jshydra to find js functions that have no callers
  • cookies.sqlite writes to disk constantly
  • expose raw access to C types for safe/simple properties in xpcom (bug 412531, bug 505907)
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