100% CPU usage from Xorg process, how to to troubleshoot?

Arodef · 07-25-2014, 05:01 PM

System was very sluggish and top revealed Xorg was using 99-100% of the CPU. OS is CentOS 5.8. I just have the desktop up, no windows besides a terminal are running. pstack trace of Xorg is below. Any ideas what the issue is?

Code:

[root@localhost ~]# ps -ef | grep Xorg
root      8786  6472 13 Jul25 tty7     02:26:04 /usr/bin/Xorg :0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7
[root@localhost ~]# pstack 8786
#0  0x00002ba945e9d0bb in ?? () from /usr/lib64/xorg/modules/libfb.so
#1  0x00002ba945e9dbaf in fb24_32GetImage () from /usr/lib64/xorg/modules/libfb.so
#2  0x00002ba9460dbdc7 in ?? () from /usr/lib64/xorg/modules/libxaa.so
#3  0x00000000004cfc7e in ?? ()
#4  0x000000000051def9 in ?? ()
#5  0x00000000004e30ec in ?? ()
#6  0x00000000004f8a69 in ?? ()
#7  0x00000000004f9249 in ?? ()
#8  0x000000000044b45a in Dispatch ()
#9  0x000000000043376e in main ()
[root@localhost ~]#

dijetlo · 07-26-2014, 07:44 AM

Normally, if their isn't a functionality problem (if the software does what it's supposed to do without throwing errors or bombing out) I've found issues related to performance are often related to drivers, or driver "type" emulations.
Looking at your list, the frame buffer driver (libfb.so) appears to fit that description. One way to check is to go here and let the web server test your frame buffer performance.

TobiSGD · 07-26-2014, 09:35 AM

High CPU usage from X usually indicates that you run on some kind of software rendering instead of using the GPU. What video hardware do you have and which driver is in use?
Please provide the output of

Code:

lspci | grep VGA
glxinfo | grep render

jdkaye · 07-26-2014, 10:14 AM

From a terminal you can run this command:

Code:

top

That should give you an idea on who's hogging your memory/cpu.
jdk