17770 2008-03-11 09:25:02 -0700 JavaScript execution is dramatically slower while Drosera is attached 2008-05-17 09:56:09 -0700 1 1 1 Unclassified WebKit New Bugs 528+ (Nightly build) All All CLOSED WONTFIX InRadar P2 Normal --- 10688 17778 1 aroben webkit-unassigned bfattori oldest_to_newest 73325 0 aroben 2008-03-11 09:25:02 -0700 JavaScript execution is dramatically slower while Drosera is attached. It's likely that much of this slowness is due to WebKit making a cross-process call to Drosera for every line of JavaScript executed, even if Drosera has no breakpoints set. 73327 1 aroben 2008-03-11 09:25:59 -0700 <rdar://problem/5792378> 73550 2 aroben 2008-03-12 23:27:37 -0700 One possible way we could solve this would be for WebKit to be aware of Drosera's breakpoints and only make cross-process calls when a breakpoint is hit or Drosera requests that we step. Another possible way to solve this would be to move debugging to be in-process (as covered by bug 17134). 73682 3 aroben 2008-03-13 22:39:54 -0700 *** Bug 17554 has been marked as a duplicate of this bug. *** 77948 4 aroben 2008-04-17 10:52:33 -0700 While a lot of the slowness surely comes from the cross-process calls, some of it definitely comes from WebCore/JSC's debugger infrastructure. Adding a single no-op JavaScriptDebugListener to WebCore's JavaScriptDebugServer caused SunSpider to be 2.42x as slow. Here are the actual results: Without a JavaScriptDebugListener: http://webkit.decenturl.com/sunspider-without-javascriptdebuglis With a JavaScriptDebugListener: http://webkit.decenturl.com/sunspider-with-a-javascriptdebuglist 77952 5 aroben 2008-04-17 11:19:35 -0700 I just tried this with Firefox 2 and Firebug. The performance was not significantly different when Firebug was disabled vs. enabled. Firebug disabled: http://webkit.decenturl.com/sunspider-without-firebug Firebug enabled: http://webkit.decenturl.com/sunspider-with-firebug 78131 6 aroben 2008-04-18 10:50:31 -0700 Strangely, changing JavaScriptDebugListener to use const KJS::UString& instead of const String& did not improve performance on SunSpider at all, even though it should reduce the number of strings allocated. 80651 7 kmccullough 2008-05-16 14:04:55 -0700 Drosera is going away and JS debugging is now happening in the WebInspector. 80822 8 timothy 2008-05-17 09:56:09 -0700 Closing since Drosera has been replaced by the new Web Inspector debugger. Moving to the New Bugs component so the Drosera component can be closed and removed.