In the nightly build for webkit the 3d portion of the animation on the home page of http://www.jtechcommunications.com suffers from bad performance. This animation is nice and smooth in Safari 7.0.3.
The animation is using the rekapi library (http://rekapi.com) to dynamically create the css animation code and inject it as a style. I suspect it's related to the latest work on the JIT css.
Disabling the dynamic css generation and simply setting the values speeds it up on the nightly build, though it is still slower than Safari 7.0.3 w/o the css. (w/o access to the code you can get the non-css generating version by setting the user agent to be chrome - we only had the css version enabled on webkit for safari)
I see WebProcess use a lot of CPU time, and frequently pause (sometimes for a second or so).
Regressing this, it looks like <http://trac.webkit.org/r155977>.
Created attachment 231920 [details]
Comment on attachment 231920 [details]
Very sad :(
(In reply to comment #4)
This appears to have broken the following tests on the WK2 bots:
Here are the results: http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK2%20(Tests)/r169229%20(5896)/results.html
Here is the build history that shows it regressed after this revision: http://build.webkit.org/builders/Apple%20Mavericks%20Release%20WK2%20(Tests)?numbuilds=50
I'll rebaseline those.