Red Hat Bugzilla – Bug 585604
X process using 100% of CPU (when using F12 kernel on RHEL-6beta)
Last modified: 2010-06-08 10:01:04 EDT
Not quite sure if this is related to 585542, but in the setup with the F12 kernel to get the Intel GPU driver working, X process is using up 100% CPU constantly. This continues to happen even if the following packages from F12 are installed instead of the RHEL6b packages to match the kernel:
Note 1: F12 with the said packages doesn't seem to suffer from this.
Note 2: KDE is being used as both DESKTOP and DISPLAYMANAGER
There don't appear to be any runnaway growing log files.
The 100% CPU usage by the X process only seems to happen when booting into run level 5, and even then, only AFTER logging in. If machine is booted into run level 3 and X started with startx, the X process DOESN'T use up excessive amounts of CPU. Interestingly, while at the X logon screen when booting into run level 5, the X process is also NOT using up CPU.
To summarize: The high CPU usage only occurs when:
1) Booting into run level 5
2) After login
Just tested this a little further - this only seems to happen when using kdm login manager. It doesn't seem to happen when using gdm. Perhaps this bug should be re-assigned to the kdm package instead of xorg-x11-server?
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(In reply to comment #0)
> Not quite sure if this is related to 585542, but in the setup with the F12
> kernel to get the Intel GPU driver working, X process is using up 100% CPU
> constantly. This continues to happen even if the following packages from F12
> are installed instead of the RHEL6b packages to match the kernel:
> Note 1: F12 with the said packages doesn't seem to suffer from this.
> Note 2: KDE is being used as both DESKTOP and DISPLAYMANAGER
Thanks for the bug report. We have reviewed the information you have provided above, and there is some additional information we require that will be helpful in our diagnosis of this issue.
* your X server config file (/etc/X11/xorg.conf, if available),
* output of the dmesg command,
* system log (/var/log/messages), and
* X server log file (/var/log/Xorg.*.log)
to the bug report as individual uncompressed file attachments using the bugzilla file attachment link above.
We will review this issue again once you've had a chance to attach this information.
Thanks in advance.
Unfortunately, I no longer have access to the machine I was testing this on. However, the symptoms look very similar to what is described in bug 523646. There is a possibility they might be related.
I have just re-observed this on a completely different machine. The original one was an Atom N450. The current one is a C2D w/ ATI X1400M. Same thing is happening.
Logs are attached separately.
Please re-open the bug.
Created attachment 421760 [details]
Created attachment 421761 [details]
Created attachment 421763 [details]
There is no xorg.conf file.
I'd appreciate it if you could mark this bug as invisible for now just in the unlikely case there's something vaguely exploitable that could be inferred from the logs I attached.
Another point to note - the current case is when using a vanilla RHEL6b setup, no F12 packages at all.
The top to CPU using processes are consistently these two:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1671 root 40 0 112m 18m 5800 R 99.4 0.6 34:10.87 X
1993 gordan 40 0 859m 22m 14m S 2.3 0.7 0:41.16 knotify4
Having looked elsewhere for possible insight into causes of this, I have found this KDE bug dating back to 2008.
Could it be related?
Created attachment 422157 [details]
10 second strace of the X process using 100% of CPU
Note: Although it is only < 70KB compressed, this extracts to about 15MB, as most lines are almost identical, and one might hope relevant to the high CPU usage.
OK, I can confirm that there is additional evidence that it is in fact the external KDE bug from 2008 that is causing this issue.
The bug in question is in KDE's powerdevil.
Removing powerdevil libraries cures the problem:
# ls -la /usr/lib64/kde4/*powerdevil*
----------. 1 root root 193992 Feb 17 14:31 /usr/lib64/kde4/kcm_powerdevilconfig.so.bak
----------. 1 root root 188936 Feb 17 14:31 /usr/lib64/kde4/kded_powerdevil.so.bak
----------. 1 root root 55120 Feb 17 14:31 /usr/lib64/kde4/krunner_powerdevil.so.bak
X process CPU usage is now back down to around 0.
This is, of course, a gross hack, but disabling KDE power management completely in this way yields far, far better battery life than running the CPU constantly at 100%.
If I am right about this, it may be worth investigating how a bug that has been patched upstream for at least 18 months has managed to get into RHEL6b.