xpapps performance

Performance meetings in Engineering Pit
Wed 1:00pm	1-877-319-3725 id=0000
Thu 1:30pm	1-877-319-3725 id=0000

Contact: Chris McAfee
$Id: index.html,v 1.45 2003/09/06 23:49:33 sspitzer%netscape.com Exp $
In addition to speeding up the layout engine, we need to look at overall app speed. This page will focus on non-page layout performance problems. Please use news://netscape.public.mozilla.performance and news://netscape.public.mozilla.porkjockeys to discuss and/or catch up on current performance activity, and add the perf and topperf keywords to bugs as appropriate.

Problem Areas

Startup (7251)
- JS/prefs loading
  - Loading prefs takes nearly a second of startup time (66877)
  - Remove obsolete prefs and files (blakeross, 33115, 62755)
- Too many nsEventListenerManagers @ startup (68074)
- Loading java & all plugins @ startup (26516)
- ~~Bookmarks parsing is O(n**2)~~ [2/20/01] Fixed
- DLL loading
  - Some DLL's are loaded to use only a few entry points, varada was looking at somehow combining these into a startup DLL to avoid loading unnecessary DLL's at startup (12896, 29249, 46800)
  - Win32: Working Set, /OUTPUT linker directive (65845)
  - Win32: Look at preloading DLL's at machine startup (36283, mcafee, pchen, law). There would be a pref to toggle this, and dynamic profile mechanism (~~ccarlen, 35559~~) would allow us to switch the profile when the user "starts the app" and chooses a profile.
- Selective CSS loading
  - Only load CSS at startup that's necessary to display the app being loaded (hewitt, 63246). Also saves memory.
- Packaging
- FastLoad of XUL (ben, 112064)
New window opening (pchen, law)
- Analysis
File I/O
- Turning cache off can improve performance dramatically, esp. on Mac
- Use strace on linux to look for unnecessary or slow file usage.
- stdout: only significant slowdown if in a tight loop
  - Nominal gain in removing thousands of unused dump()s, repetitive debug() functions, and other cruft (blakeross, 65127)
- Excessive stat() calls (29063)
  - We seem to stat() right before many calls to open() and readlink(). Need to look at nsIFileSpec constructor, and/or usage.
Event model (saari, heikki, joki)
- Implement priority event handling to give precedence to UI and chrome events, speeding them up and making them more responsive (danm, 50104).
- Start looking at DOM event propogation and possible recursion cases. saari suggests debugging events in nsPresShell to start.
- Look at PL (NSPR) events using NSPR log mechansim.
- Look at nsGUIEvents
  - Blizzard's Xlib interleaving hack (67370)
Layout problems @ xpapps level
- Poor incremental reflow in text control leads to slow typing with complicated content after the text control (attinasi, 67495)
Tree-based UI
- Use sspitzer's batch API hack to speed up multiple tree item delete for bookmarks, waiting on 66583
- RDF-based tree performance problems will be fixed when RDF-based trees are able to convert to (waterson, 71530)
- ~~New outliner element for instant loading, column sorting and scrolling (hyatt)~~ [3/6/01] Enabled on trunk
Chrome complexity (CSS, JS, overlays)
- Unnecessary CSS loaded for each window open? Mailnews team tried reducing style rules and didn't find much gain here (hewitt, sspitzer)
- What is the cost of using an overlay?
- Precompile JS and load it incrementally (brendan, 68045)
History
- Session history (radha, rpotts)
  - Set boundaries on growth.
- Global history (alecf)
  - Startup and use of browser can drag if too many files in global history.
    - User-defined limits on growth.
    - Improve mork performance -- small db that wasn't designed for large amounts of data or performance (bienvenu).
- New cache (gordon, beard)
Imglib2/libpr0n (pavlov, saari, pnunn, tor)
- Animated images should be cached (41268)
- ~~Throbber and progressbar cause slowdown (hyatt)~~ [2/8/01] Fixed by not resolving style when value attr. changes
  - ~~~21% speedup on win32, similar speedup on mac, linux~~
- New image cache (pavlov).
PSM in-process / psm2 (bryner, javi, thayes, lord)
- Complete integration with Mozilla
- Modularity
- In-process
Cookies (morse)
- Writing entire cookie file for each page cookie.
Strings (scc, dbaron)

Filed Performance Bugs

Trends/Data

Things to Do

Organize a tasks list for who's doing what.

Are people actually working on the above? Need to get organized and get busy.

Post daily/weekly performance data derived from automated testing.
- Get with Netscape QA to create browser timing tests similar to the Mail/News performance page. (mcafee, paw)
- Produce mozilla/embedding delta data(mcafee, jrgm)
Post startup times in the daily reports (jrgm)
Post runs of Quantify, jprof, eazel, strace
- Can QA do this? Engineers should be focused on fixing, not profiling.
Post jrgm test suite to mozilla.org (mcafee)

Team Contact Info

Related Sites

Chris McAfee, Blake Ross