Created attachment 284396 [details] [HTML] Reduction This regressed in: https://trac.webkit.org/changeset/202876/trunk/Source/WebInspectorUI/UserInterface/Views/TabBrowser.js Steps: 1. Open attached reduction 2. Open Web Inspector 3. Open Console tab 4. Clear console 5. Reload the page 6. Click on Debugger tab Expected: Debugger tab opens in <0.5 seconds Actual: Web Inspector UI becomes unresponsive for 2-3 seconds before it opens Debugger tab. rdar://problem/27431121
Created attachment 284397 [details] Patch
Created attachment 284399 [details] [Image] Before/After
With the patch applied, I was unable to reproduce bug 158069. cq- because I don't yet understand the change that was made in that bug.
(In reply to comment #2) > Created attachment 284399 [details] > [Image] Before/After Hm, I'm getting different results every time. I'm still seeing 2-3x performance improvement on average.
Comment on attachment 284397 [details] Patch r=me, Tim's review comment at the time made this change unnecessary anyways, so win win!
Comment on attachment 284397 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=284397&action=review > Source/WebInspectorUI/ChangeLog:11 > + (WebInspector.TabBrowser.prototype._tabBarItemSelected): > + Showing NavigationSidebar before removing previous TabContentView can be very slow when > + TabContentView is ConsoleTabContentView with a lot of messages. This comment just says "can be slow" but doesn't state the reason WHY it is slow. In this case, I believe the WHY was because it caused extra forced layouts because of the order of operations (show sidebar, change content view, show sidebar) instead of (change content view, show sidebar, show sidebar).
Created attachment 284403 [details] Patch
Comment on attachment 284403 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=284403&action=review > Source/WebInspectorUI/ChangeLog:9 > + TabContentView is ConsoleTabContentView with a lot of messages because of the order of operations: Again "because of the order of operations" doesn't explain what is slow. It is because this different order of operations triggered MORE forced layouts.
Created attachment 284404 [details] Patch
Comment on attachment 284404 [details] Patch Clearing flags on attachment: 284404 Committed r203636: <http://trac.webkit.org/changeset/203636>
All reviewed patches have been landed. Closing bug.