Issue 236111 in chromium: Rapid flickering, Chrome uses 100% CPU, is repeatable

[chro...@googlecode.com]

Status: Unconfirmed
Owner: ----
Labels: Type-Bug Pri-2

New issue 236111 by TheRya...@gmail.com: Rapid flickering, Chrome uses
100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

Chrome Version : Version 26.0.1410.65
URLs (if applicable) :
http://en.wikipedia.org/wiki/Cellophane_(disambiguation)
Other browsers tested:
Safari 5: FAIL

What steps will reproduce the problem?
1. go to http://en.wikipedia.org/wiki/Cellophane_(disambiguation)
2. make your window the same size as this:
https://dl.dropboxusercontent.com/u/13042716/ChromeBug.tiff
(the actual size for you to see the bug may differ slightly, if you dont
use the same fonts or something)
3. watch (you can't see the bug in the screen shot)

What is the expected result?
Page should be static, and Chrome should behave.

What happens instead?
Page rapidly flickers, and Chrome uses 100% CPU.

break down:
1. The page renders without scroll bar, and it is long enough to warrant a
scroll bar
2. Adds a scroll bar, which rearranges the page making it narrower but due
to the layout of the page, also shorter and causes it to not need a scroll
bar.
3. see step 1

This also happens in Safari at this specific size.

Attachments:
ChromeBug.tiff 304 KB

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[chro...@googlecode.com]

Updates:
Labels: Performance OS-Mac

Comment #1 on issue 236111 by meh...@chromium.org: Rapid flickering, Chrome

uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

(No comment was entered for this change.)

[chro...@googlecode.com]

Updates:
Labels: -Cr-Internals-GPU Cr-Blink-Rendering

Comment #3 on issue 236111 by vang...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

Not really a GPU problem. It sounds like a Blink layout/rendering issue.

[chro...@googlecode.com]

Updates:
Status: Assigned
Owner: wangx...@chromium.org

Comment #7 on issue 236111 by wangx...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

I'd like to work on this bug.

[chro...@googlecode.com]

Comment #9 on issue 236111 by wangx...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

Correction to #8: updateScrollbars() is called recursively (depth=1) when
the content size is 978x594 and 993x591.

The page contains the following CSS rule:

@media screen and (min-width:982px) {
...
}

The rule for wider screen produces higher layout (993x594) than the default
rules does (978x591).

There are also some transition animations on some elements. The sizes
978x594 and 993x591 are temporary sizes after the vertical scrollbar is
created/removed at the beginning of the transition animation. The
combination of the abnormal @media rule and the transition animation causes
the flickering.

This looks a fundamental problem of non-overlay scrollbars. I'd mark this
issue WontFix, or suggest outreach to wikipedia.

Attached the reduced test case.

Attachments:
testflicker.html 588 bytes

[chro...@googlecode.com]

Comment #10 on issue 236111 by jam...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

If we could detect this case the right thing to do would be to add a
disabled vertical scrollbar to the page. Detecting it in the case of
@media + transitions might be hard.

If we wanted to treat this as an evangalism bug, what would our
recommendation to wikipedia be?

[chro...@googlecode.com]

Comment #14 on issue 236111 by taba...@google.com: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

The spec seems wrong - MQs need to be based on the device's capabilities,
disregarding any content or styles. Otherwise, you run into trivial
circular dependencies.

Allowing scrollbars to influence the 'width' MQ violates both of these - it
depends on the page's content *and* styles. That's super-bad.

We should switch to ignoring scrollbars all the time, and give feedback to
the CSSWG that this needs to be changed.

[chro...@googlecode.com]

Comment #15 on issue 236111 by trc...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

I believe the CSS spec is saying the same thing. By "including the size of
a rendered scrollbar", it means to use the total width of the viewport,
e.g. not subtracting the space used by scrollbars.

[chro...@googlecode.com]

Comment #16 on issue 236111 by wangx...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable
http://code.google.com/p/chromium/issues/detail?id=236111

The spec seems correct to me about ignoring scroll bars: "including the
size of scroll bars".

This bug is because the size of scrollbars are excluded from the viewport
size causing scrollbars to influence the width MQ rule.

[chro...@googlecode.com]

Comment #17 on issue 236111 by bugdro...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable

http://code.google.com/p/chromium/issues/detail?id=236111#c17

------------------------------------------------------------------------
r149832 | wangx...@chromium.org | 2013-05-07T01:10:38.001934Z

Changed paths:
A
http://src.chromium.org/viewvc/blink/trunk/LayoutTests/fast/media/mq-size-include-scrollbars-expected.html?r1=149832&r2=149831&pathrev=149832
A
http://src.chromium.org/viewvc/blink/trunk/LayoutTests/fast/media/mq-size-include-scrollbars.html?r1=149832&r2=149831&pathrev=149832
M
http://src.chromium.org/viewvc/blink/trunk/Source/core/css/MediaQueryEvaluator.cpp?r1=149832&r2=149831&pathrev=149832
M
http://src.chromium.org/viewvc/blink/trunk/Source/core/platform/ScrollView.h?r1=149832&r2=149831&pathrev=149832
M
http://src.chromium.org/viewvc/blink/trunk/Source/core/platform/ScrollView.cpp?r1=149832&r2=149831&pathrev=149832

Include scrollbar size in @media width/height

Not including scrollbar size causes bad circular dependencies when
non-overlay scrollbars are created or removed.

CSS spec says we should include size of scroll bars when evaluate the
MQ rules about width/height.

BUG=236111
TEST=LayoutTests/fast/media/mq-size-include-scrollbars.html

Review URL: https://chromiumcodereview.appspot.com/14659008
------------------------------------------------------------------------

[chro...@googlecode.com]

Updates:
Status: Fixed

Comment #18 on issue 236111 by wangx...@chromium.org: Rapid flickering,

Chrome uses 100% CPU, is repeatable

http://code.google.com/p/chromium/issues/detail?id=236111

(No comment was entered for this change.)