Bug 101522 - Web Inspector: Identify high-cost CSS declarations
Summary: Web Inspector: Identify high-cost CSS declarations
Status: RESOLVED WONTFIX
Alias: None
Product: WebKit
Classification: Unclassified
Component: Web Inspector (show other bugs)
Version: 528+ (Nightly build)
Hardware: All All
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2012-11-07 16:50 PST by Paul Irish
Modified: 2015-10-28 13:42 PDT (History)
17 users (show)

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Description Paul Irish 2012-11-07 16:50:04 PST 
In the lifetime of an app, costly style rules can affect both transition/scroll FPS and application performance.
The costs will manifest as extra time spent in style recalc, reflow, paint, compositing.

Right now, there is no strong way to attribute the long bars in Timeline back to authored CSS rules, though I feel that delivers the most insight to the user.

I wanted to open up this ticket to discuss and track any progress on this front.

Some ideas I've heard so far:
* rendering performance heatmap
* element paint cost profile report
* zooming into Timeline bars for RenderTree breakdown
Comment 1 Radar WebKit Bug Importer 2014-12-01 14:29:20 PST 
<rdar://problem/19106888>
Comment 2 BJ Burg 2015-10-28 13:32:51 PDT 
Is CSS really a bottleneck anymore with the CSS JIT?
Comment 3 Timothy Hatcher 2015-10-28 13:42:35 PDT 
Nope. We removed the CSS profiler a while ago too.