High CPU usages rendering X display which is not visible (e.g. after user switch)

[Benjamin Horstman]

Binary package hint: compiz

Description:
After switching to second user (who is using metacity, of course), compiz.real uses lots (20-100%) of CPU drawing. This only happens when the display compiz is running on (:0 for me) is NOT actually what's being output. Secondly, this only occurs if something is updating on the compiz screen (e.g. htop maximized is real bad). This does include the lock screen (which displays completely white for me, though I can guess where the password box is via cursor; probably an unrelated bug) Note that prior to the user switch CPU usage is basically none (<1.5%).

Workaround:
Switch to a blank desktop before the user switch. This pins CPU usage at about 5%. Probably if I removed system monitor applet, clock, etc. the usage would be the same.

My System:
Stock hardy w/ current nvidia-glx-new. First user uses dual monitors in Twinview configuration, second user uses TV/laptop screen in Twinview configuration.

[Rich (rincebrain)]

Could you report the exact versions of the compiz, compiz-core, and compiz-gnome via "apt-cache policy [package name]"?

[Benjamin Horstman (yodenss)]

bph6@bph6-ubuntu:~$ apt-cache policy compiz
compiz:
  Installed: 1:0.7.4-0ubuntu6
  Candidate: 1:0.7.4-0ubuntu6
  Version table:
 *** 1:0.7.4-0ubuntu6 0
        500 http://us.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status
bph6@bph6-ubuntu:~$ apt-cache policy compiz-core
compiz-core:
  Installed: 1:0.7.4-0ubuntu6
  Candidate: 1:0.7.4-0ubuntu6
  Version table:
 *** 1:0.7.4-0ubuntu6 0
        500 http://us.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status
bph6@bph6-ubuntu:~$ apt-cache policy compiz-gnome
compiz-gnome:
  Installed: 1:0.7.4-0ubuntu6
  Candidate: 1:0.7.4-0ubuntu6
  Version table:
 *** 1:0.7.4-0ubuntu6 0
        500 http://us.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status

[Pedro Villavicencio (pedro)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering is this still an issue for you? Could you try to reproduce the same with Ubuntu 8.10 or 9.04? Thanks in advance.

[Pedro Villavicencio (pedro)]

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to New. Thanks again!.

[Ian Johnston (ian-orbister)]

Reporting another case

[Ian Johnston (ian-orbister)]

I am seeing precisely this problem. The culprit in my case was a Cairo clock with the seconds hand displayed. With that displayed on an otherwise blank desktop, CPU use is negligible. If I then switch to another user (without the clock), one CPU stays pegged at 100%. Removing the Cairo clock from the first desktop solves the problem in this case ... but it reappears whenever /anything/ tries to update the desktop for a non-active user.

As requested from the Other Guy, here are my compiz versions

compiz:
  Installed: 1:0.8.2-0ubuntu8
  Candidate: 1:0.8.2-0ubuntu8
  Version table:
 *** 1:0.8.2-0ubuntu8 0
        500 http://gb.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status

compiz-core:
  Installed: 1:0.8.2-0ubuntu8
  Candidate: 1:0.8.2-0ubuntu8
  Version table:
 *** 1:0.8.2-0ubuntu8 0
        500 http://gb.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status

compiz-gnome:
  Installed: 1:0.8.2-0ubuntu8
  Candidate: 1:0.8.2-0ubuntu8
  Version table:
 *** 1:0.8.2-0ubuntu8 0
        500 http://gb.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status

In case it's of interest, I'm using an nVidia FX5200 and the proprietary drivers:

nvidia-glx-173:
  Installed: 173.14.16-0ubuntu1
  Candidate: 173.14.16-0ubuntu1
  Version table:
 *** 173.14.16-0ubuntu1 0
        500 http://gb.archive.ubuntu.com jaunty/restricted Packages
        100 /var/lib/dpkg/status