RESOLVED WONTFIX 90151
Element::attributeChanged could be devirtualized 
https://bugs.webkit.org/show_bug.cgi?id=90151
Summary Element::attributeChanged could be devirtualized
Hajime Morrita
Reported 2012-06-28 03:32:03 PDT
There are only two overrides (StyledElement and SVGElement) thus easily devirtualized.
Attachments
Add attachment proposed patch, testcase, etc.
Hajime Morrita
Comment 1 2012-06-28 20:54:17 PDT
The benchmark didn't show any speedup. closing.
Kentaro Hara
Comment 2 2012-06-28 21:12:44 PDT
I've tried a couple of devirtualization, but I couldn't observe any performance improvement. It looks difficult to get a perf win by devirtualization.
Ryosuke Niwa
Comment 3 2012-06-28 21:25:51 PDT
I think we should devirtualize functions if we can. The gain is small but if small improvements add up. The corollary of this is that virtualizing functions may not cause a significant performance regression by itself but will eventually add up.
Ryosuke Niwa
Comment 4 2012-06-28 21:28:22 PDT
Also note that most modern x86 processors do indirect branch predictions. If we really wanted to see the perf. improvements for devirtualization, we should be testing on ARM and architectures where such isn't implemented.
Hajime Morrita
Comment 5 2012-07-01 17:38:30 PDT
This is off-topic but having ARM perf bot will be huge positive leap for us.
Note You need to log in before you can comment on or make changes to this bug.