Performance/Status Meetings/2008-January-16

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Gecko 1.9 Performance and Leaks Meeting Details

• Wednesdays - Firefox 3 - 10:00am Pacific, 1:00pm Eastern
• Script Conference Room, Building S, Mountain View
• 650-903-0800 or 650-215-1282 x91 Conf# 217 (US/INTL)
• 1-800-707-2533 (pin 369) Conf# 217 (US)
• irc.mozilla.org #perf for backchannel

Leaks

• Lots of leaks with extensions.
  • Many look like shut-down leaks. Would still be good to get these fixed so that we know for sure that they are shut-down leaks, and to make it easier to find other leaks. Have been giving these P3 priority.
  • Some do not look like shut-down leaks, have been marking these P1 or P2.
  • Will test which cause leaks that grow over time and make sure these are given top priority.
• Tomcats testing procedure documented here: [1] and leak testing plan here [2]
• Peterv has a patch to fix bug in cycle collector that causes many random crashes bug 407034, and a patch to fix one source of hidden-window-leaks which is likely source of many extension leaks bug 412491.
• More progress on making DEBUG_CC more useful by dbaron bug 410116. Seems mostly fixed.
• We need better tools in non-debug builds that extension authors can use for leak testing. Leak gauge should already work?

Action Items

• AI:sicking Look into enabling trace-refcount, without the tracing part in nightlies.
• AI:cbarrett Look into OS leaks on Mac.
• AI:dbaron Make assertions fatal on new windows leak box.
• AI:sicking Test leaked handles on windows manually using purify.
• AI:sayrer Run leak buster while looking for trace-malloc leaks. [didn't get this done--sayrer]
• AI:sicking to go through and prioritize leak bugs

Performance

• Alix wonders about areas where we improved FF2->FF3. We want this for documentation purposes. Email alix with any things you know we have improved (@mozilla.com)
  • For features page on main mozilla.com website
  • For press reviewers' guide
  • Needs concrete examples of speedups (pages, percentages, etc.)
  • Will wait until b3 to have concrete numbers
  • Concrete details: work that's happened, benchmarks that we're using, and what we expect in real-world usage

• JPEG/image speedups
  • bug 411379: JPEG color conversion MMX/SSE2
  • Shows perf wins on win32, OSX has bug 412396
  • bug 411718: avoid buffer copy on JPEG decode

• Perf Bugs for FF3:
  • http://tinyurl.com/yub492

• Txul platform differences according to mac mini machines
  • mac: slowest on 1.8, slower still on 1.9 (30% regression) Looks even or better than branch
  • windows: fastest on 1.8, now in second place (30% regression) -- improving, still slower
  • linux: middle on 1.8, now fastest on 1.9 (30% improvement)

• massive Ts regression in 2006
  • Ts analysis: bug 406810
  • Related to thread manager landing
  • Darin thinks it might be excessive painting.

• Profile Guided Optimization
  • WPO turned on for windows (bug 361343) -- nice performance win on XP
  • Spidermonkey seems to respond well to PGO under GCC (bug 410994)
  • sayrer has entire browser building with -fprofile-generate on Linux. no results yet.
  • dbaron: shipped fx 1.0 with PGO on linux as well, was a 10% perf win... but compiler upgrade + build system breakage stopped us. We need to restart this on linux (and see about OSX).
  • -GL breaks some things on win32

• bug 353962 -- JS spinlocks vs. full locks (Crashes in Fx2)
• bug 196843 -- CSS fastload

• On radar (unowned stuff that people have mentioned have mentioned we should look at at some point)
  • Theme optimization
  • roc's scrollbar issues
  • startup performance (fastload perf, loading libXUL and other files, etc.) (unowned)
  • more work to speed up onSecurityChange, but further work will require SSL work and reducing the number of notifications
  • XPConnect accessor speed (bug 412531) (request for priority+owner by dietrich)

• Start/Stop Shark from JS (bug 411365 Patch)
  • Gets really clean profiles.
  • Install newest CHUD
  • Start Shark App.
  • Good setting for brief events is config->advanced 20us sample rate
  • Put shark in remote mode
  • Example from bug 412396 test:

 <html>
 <head>
 <title>Test JPEG Rendering Time - (Hacked from scragz' test)</title>
 <script type="text/javascript">
 
 connectShark();
 startShark(); // Start sampling
 
 startDate = new Date();
 startTime = startDate.getTime() / 1000;
 window.onload = function () {
   var ignoreMe = document.body.offsetWidth;
   var endTime = new Date();
 };
 window.scrollBy(0,1);
 function calceRenderingTime() {
 
   stopShark(); // Stop sampling 
   disconnectShark();
 
   endDate = new Date();
   endTime = endDate.getTime() / 1000;
   alert(endTime - startTime);
 }
 </script>
 </head>
 <body onload="calceRenderingTime();">
 ...

Action Items

• make faster

Fragmentation

• bug 407459 -- Hook up jemalloc to our build
  • ported to windows, mac and linux. integrated to build system on mac and linux. windows work continuing. Hope to have numbers by end of the week.
• bug 403830 -- Content arena
  • bug 408720 -- Fallout
  • New arenas
• Other bugs (should have perf and footprint keywords)
  • bug 403354 -- Get rid of nsCStringArray ParseString usage (maybe fixed?)
  • bug 407442 -- nsEventListenerManager allocates a lot [patch]
  • bug 408113 -- JS reallocate context->stackPool arenas way too often [patch]
  • bug 408301 -- XPConnect wrappers w/o XPConnect proto don't share JS scopes with their protos. [patch]
  • bug 410250 -- nsID/nsJSID stupid mallocs [patch]
  • bug 410357 -- use nsAutoTArray for nsCSSDeclaration::mOrder [patch]
  • bug 410392 -- stack allocate gfx objects [patch, needs work]
  • bug 408921 -- Arenas size+header are too big for size classification

Action Items

• fix things