597893 - Use animation-scheduling API for <marquee> scrolling

Status: RESOLVED WORKSFORME

(Core :: Layout, enhancement)

Description

[Michael Wu [:mwu]]

Attachment: Use animation scheduling API

This makes pages that use many <marquee>s behave better and use less cpu when the page isn't the active tab. One page (with 50 marquees) that pegs my CPU at ~95% drops to 15-20% with this patch when switching away from that tab. Without this patch, that tab continues to peg the CPU.

Comment 1

[Martijn Wargers (dead)]

The patch seems to stop marquees entirely in background tabs. Is that what we want to happen. That's not what IE8 is doing.

Comment 2

[Martijn Wargers (dead)]

Attachment: testcase1

This gives an alert when the marquee bounces. That doesn't happen with the patch in a background tab.
Also with the patch, when the file is loaded, then the window is minimized, the alert fires, but then the alert isn't displayed. I guess that might be a bug in the animation-scheduling api.

Comment 3

[Martijn Wargers (dead)]

Attachment: testcase2

With the patch, the marquee in the testcase doesn't run. It does work fine in builds without the patch and in IE8.

Comment 4

[Michael Wu [:mwu]]

One of the goals of the animation scheduling api was being able to throttle animations in background tabs. I think one option was to fire the animation once per second. Don't know if that was implemented but it sounds like it may have been. We can make this code a bit smarter and skip a bunch of steps if the time since the last animation was too long, and fire events as necessary.

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

We should be firing mozRequestAnimationFrame once per second in background tabs. Is that not happening?

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee didn't login in Bugzilla in the last 7 months.
:dholbert, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 7

[Daniel Holbert [:dholbert]]

The problem described in comment 0 is no longer an issue. Coincidentally I (and others) just looked at a case of this in bug 1754868, and we confirmed (in performance profiles) that marquees in background tabs take no CPU.