145899 2015-06-11 14:57:47 -0700 Poor scrolling performance with large complex table 2015-06-12 08:29:55 -0700 1 1 1 Unclassified WebKit Tables 528+ (Nightly build) Unspecified Unspecified NEW http://www.yeastgenome.org/cgi-bin/FUNGI/alignment.pl?locus=YBR140C P2 Normal --- 1 gsherloc webkit-unassigned cdumez kling koivisto simon.fraser zalan oldest_to_newest 1101426 0 gsherloc 2015-06-11 14:57:47 -0700 Go to bug url (http://www.yeastgenome.org/cgi-bin/FUNGI/alignment.pl?locus=YBR140C) Wait for page to load Scroll down Expected results: Smooth scrolling through the document Actual results: Often shows no rendered content for several seconds, pauses, stutters and locks up Tested with release Safari and r185452 1101489 1 zalan 2015-06-11 22:34:17 -0700 This is a table heavy page. I bet that's the reason why the Web process locks up. 66 <table> 2500 <tr> 150K <td> 123K <tt> Chromes handles it relatively okay. (better than WebKit trunk) 1101588 2 zalan 2015-06-12 08:29:33 -0700 While loading the page we spend significant amount of time in pumpTokenizer (28%) -> SegmentedString::operator= (25%) and WTF::Deque<SegmentedSubString>::destroyAll (11%) Also Style::resolveTree() (11%) After finished loading another round of style resolving kicks in with Style::resolve(37.2%) -> getUncachedPseudoStyle(13%) While scrolling, we spend most of the time in cell painting -> text drawing.