High CPU load (above 50%) on Xorg process when browsing low graphic intensive sites

[shankao]

While using grooveshark.com, I noticed a big bump in the Xorg process CPU usage after selecting its tab. It jumps from the usual >5% to more than 50%.
The webpage is not graphical intensive, but the interface is all HTML5.
I'm attaching a video that shows the effect. Note that the recording also adds some weight to the Xorg process, but it's still noticeable, from 20% to 50%.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: chromium-browser 20.0.1132.47~r144678-0ubuntu6
ProcVersionSignature: Ubuntu 3.5.0-17.27-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu1
Architecture: amd64
Date: Tue Oct 9 19:26:08 2012
Desktop-Session:
 DESKTOP_SESSION = ubuntu
 XDG_CONFIG_DIRS = /etc/xdg/xdg-ubuntu:/etc/xdg
 XDG_DATA_DIRS = /usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/
EcryptfsInUse: Yes
Env:
 MOZ_PLUGIN_PATH = None
 LD_LIBRARY_PATH = None
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcEnviron:
 LANGUAGE=en_SG:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_SG.UTF-8
 SHELL=/bin/bash
SourcePackage: chromium-browser
UpgradeStatus: Upgraded to quantal on 2012-05-15 (146 days ago)
chromium-default: CHROMIUM_FLAGS=""
gconf-keys: /desktop/gnome/applications/browser/exec = b'/usr/bin/chromium-browser\n'/desktop/gnome/url-handlers/https/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/https/enabled = b'true\n'/desktop/gnome/url-handlers/http/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/http/enabled = b'true\n'/desktop/gnome/session/required_components/windowmanager = b''/apps/metacity/general/compositing_manager = b''/desktop/gnome/interface/icon_theme = b'ubuntu-mono-dark\n'/desktop/gnome/interface/gtk_theme = b'Ambiance\n'

[Bryce Harrington (bryce)]

Unlikely to be X causing this. See https://wiki.ubuntu.com/X/Troubleshooting/HighCPU

[shankao (shankao)]

I agree that is not the cause, but it affects it (so I marked it as such)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Karl Frisk (karl-frisk)]

I believe this is a problem that roots in unity, compiz and xorg working together. ANY application that continously updates the screen causes compiz AND xorg cpu usage to go up. Examples that trigger the problem include HTML5-animated-websites, moving around terminal windows with the mouse, the spectrum analyzer in audacious, and flash animations/videos.

On my machine (Thinkpad t430 with Intel i7 3520M and Intel HD 4000 graphics) the cpu usage in Precise was already much too high: After a fresh boot open two terminals, start top in the one and keep moving around the other one. Xorg and compiz together use 10-20% cpu.

In Quantal the same experiment results in 20-40% cpu usage. For nothing but moving a small window around.

[Ari (ari-lp)]

I can confirm this bug but I'll have to disagree with Karl. This problem seems to be unrelated to the DE in use as I am experiencing it on Openbox, LXDE and Unity.

I can easily reproduce this bug by accessing any type of HTML5 website. Here are some examples:

http://fff.cmiscm.com/#!/main
http://sidigital.co/
http://www.whitehouse.gov/issues/preventing-gun-violence

As for CPU load when moving around windows, the CPU usage does seem to be higher than necessary (~15% on LXDE at the specs outlined below). Is this how it's supposed to be?

Some additional information:

- reproducible both with FF and Chrome
- mean CPU load on HTML5 website ~30% with Core i5 @ 2.66GHz
- graphics: AMD HD5650 Mobility Radeon on FGLRX (Catalyst 12.6)