742625 - Checkerboarding is worse while pages are loading

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

See video at

http://people.mozilla.com/~cjones/cnn-checkerboarding.mp4

This is cnn.com loading on a Nexus S.

There are two issues here
 - checkerboard-to-black on initial panning.  We should never do that.  Instead we should be drawing a real checkerboard, which does start happening later.
 - unpainted areas taking seconds to fill in.  This happens during the loading of cnn.com.  It might be that content JS is hogging the event loop, or we might not be interrupting reflow etc. often enough, but in any case it's janky.  The repaint latency is lower after waiting a while for content to load.

Needs analysis.

Comment 1

[Joe Drew (not getting mail)]

(In reply to Chris Jones [:cjones] [:warhammer] from comment #0)
>  - checkerboard-to-black on initial panning.  We should never do that. 
> Instead we should be drawing a real checkerboard, which does start happening
> later.

Possibly/probably bug 740303.

Comment 2

[Joe Drew (not getting mail)]

We should profile this to find out where we're spending time. If it's reflow, we can presumably fix it with ireflow. If it's something else, fixing it will be harder.

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Don't understand the generalization here, but as long as we know what's going on with cnn.com I'm happy.  It may very well be choking itself out with long-running script.

Comment 4

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Much better in latest builds.