Bug 125952 – REGRESSION(r155201): 13-14% on Dromaeo/jslib-style-prototype and 3-4% on jslib-modify-prototype

• Status: NEW
• Component: JavaScriptCore

[Ryosuke Niwa]

https://perf.webkit.org/#mode=charts&chartList=%5B%5B%22mac-lion%22%2C%22Dromaeo%2Fjslib-modify-prototype%3ARuns%22%5D%2C%5B%22mac-mountainlion%22%2C%22Dromaeo%2Fjslib-modify-prototype%3ARuns%22%5D%5D&days=168&zoom=%5B1377934353465.6045%2C1379239368520.3296%5D

WebKit: http://trac.webkit.org/log/?rev=155207&stop_rev=155196&verbose=on

[Ryosuke Niwa]

Also regressed Dromaeo/jslib-style-prototype by 12-13%!

https://perf.webkit.org/#mode=charts&chartList=%5B%5B%22mac-mountainlion%22%2C%22Dromaeo%2Fjslib-style-prototype%3ARuns%22%5D%2C%5B%22mac-lion%22%2C%22Dromaeo%2Fjslib-style-prototype%3ARuns%22%5D%5D&days=227&zoom=%5B1377861956112.884%2C1379566406980.915%5D

[Radar WebKit Bug Importer]

<rdar://problem/15711024>

[Ryosuke Niwa]

Bisected locally. It appears that this regression is caused by http://trac.webkit.org/changeset/155201.

Perhaps one of these tests is encountering a horrible performance cliff the patch talks about.

[Ryosuke Niwa]

Created attachment 220501 [details]
Perf test results