56141 2011-03-10 13:40:43 -0800 REGRESSION(r74538): 140% slowdown on scrolling-boxes demo. 2011-03-10 19:56:02 -0800 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Mac (Intel) OS X 10.6 RESOLVED INVALID http://people.mozilla.org/~roc/scrolling-boxes.html InRadar, Regression P1 Normal --- 1 rniwa webkit-unassigned aestes ariya.hidayat eric hyatt jamesr koivisto mitz noam simon.fraser oldest_to_newest 365492 0 rniwa 2011-03-10 13:40:43 -0800 Using r80210, the following demo takes 8619ms whereas it only takes 2505ms on Safari 5 http://people.mozilla.org/~roc/scrolling-boxes.html 365497 1 rniwa 2011-03-10 13:46:23 -0800 r73316: ok r74228: ok r75294: bad r75891: bad r76640: bad 365689 2 ap 2011-03-10 17:21:50 -0800 <rdar://problem/9119011> 365704 3 aestes 2011-03-10 17:47:11 -0800 It seems like there have been multiple regressions. Due to one of these two changes: http://trac.webkit.org/changeset/74538 http://trac.webkit.org/changeset/74539 I see a 140% slowdown (~2000ms to ~4800ms). There is another slowdown somewhere between r74539 and ToT, which gets times ~8000ms. I'll see if I can track down that regression as well. 365710 4 aestes 2011-03-10 17:51:07 -0800 The second regression is due to <http://trac.webkit.org/changeset/77101> I think. 365730 5 aestes 2011-03-10 18:46:33 -0800 The first regression is caused by <http://trac.webkit.org/changeset/74538>, which turned on support for non-prefixed box-shadow. 365732 6 aestes 2011-03-10 18:53:35 -0800 I filed <https://bugs.webkit.org/show_bug.cgi?id=56162> to track the second slowdown. 365740 7 aestes 2011-03-10 19:01:58 -0800 The demo uses non-prefixed box-shadow, so presumably if it had used -webkit-box-shadow instead, this demo would have been slower in Safari 5 as well. Since we just weren't applying the box-shadow before r74538, this doesn't seem like an actual regression. I think <https://bugs.webkit.org/show_bug.cgi?id=56162> is still valid though, especially since r77101 claims to improve scroll performance. 365745 8 aestes 2011-03-10 19:07:56 -0800 Yea, Safari 5 gets the same performance numbers as r74538 if I change the test to use -webkit-box-shadow instead of box-shadow. 365746 9 aestes 2011-03-10 19:09:58 -0800 I think that fact makes this bug invalid, but <https://bugs.webkit.org/show_bug.cgi?id=56162> still seems like a legitimate regression. 365778 10 rniwa 2011-03-10 19:56:02 -0800 Thanks for the analysis, Andy!