[webkit-dev] optimizing browser handling of Facebook Timeline scrolling

Geoffrey Garen ggaren at apple.com
Tue Feb 14 12:17:56 PST 2012

> If anyone needs a test page, you can log in as my test user
> styoung.travel at gmail.com (pwd:browsertest). Then go to
> https://www.facebook.com/styoung.


I took a trace of this timeline and saw similar results as before (lots of time computing .offsetHeight and .scrollLeft), but with less time spent in image drawing. (Perhaps I have higher resolution photos in my timeline.)

> Btw, what tool are you using that tells you what item is being
> repainted when the cpu is pegged?

Mac OS X ships with a performance analysis tool called "Instruments".

Documentation overview:


Recent WWDC presentation:


Instruments analysis doesn't work very well with the current shipping version of WebKit, but it works great with WebKit nightly builds (nightly.webkit.org).


More information about the webkit-dev mailing list