Description of problem: Found JavaScript Runfield demo - it works great in WebKit but it is not playable in Firefox. Version-Release number of selected component (if applicable): firefox-11.0-1.fc16.x86_64 xulrunner-11.0-3.fc16.x86_64 How reproducible: Always. Steps to Reproduce: http://www.mozilla.org/en-US/firefox/features/ -> http://mozillademos.org/demos/runfield/demo.html Jump over holes. Actual results: On almost each jump it gets stuck for about 0.5sec, the game is not playable. Expected results: Normal playable game like in: epiphany-3.2.1-3.fc16.x86_64 webkitgtk3-1.6.1-1.fc16.x86_64 Additional info: xorg-x11-server-Xorg-1.11.4-3.fc16.x86_64 xorg-x11-drv-intel-2.17.0-8.fc16.x86_64 00:02.0 0300: 8086:0126 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
I can reproduce. This seems to be related to sound. If I turn sound/music off I don't see this problem anymore.
Much better visible is WebKit<->Gecko slowness in another HTML5 game: http://www.adityaravishankar.com/projects/games/command-and-conquer/
Upstream bug: https://bugzilla.mozilla.org/show_bug.cgi?id=743972
Maybe it is not yet perfect but with Firefox 12 the major performance issue is gone, the Comment 2 demo also works fine now.
Okay, I can see significant improvement too. I think we can close it as current release. Feel free to reopen if reoccurs.