98734 2012-10-09 02:31:27 -0700 enclosingLayer() walks the entire parent chain, making it slow for deep trees 2012-10-31 08:28:12 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified NEW P2 Normal --- 98798 1 eric webkit-unassigned jamesr jchaffraix simon.fraser tonikitoo oldest_to_newest 737589 0 eric 2012-10-09 02:31:27 -0700 enclosingLayer() walks the entire parent chain, making it slow for deep trees It makes repaint/layout samples account for about 30% of: http://www.robohornet.org/tests/descendantselector.html (which I'm not suggesting is either a good or bad benchmark, merely one which triggers this condition.) 737913 1 simon.fraser 2012-10-09 10:21:57 -0700 I assume you mean "slow for deep, layer-sparse trees"? 739133 2 eric 2012-10-10 11:03:21 -0700 Yes, deep, layer-sparse. :)