2

For some reason one of my CPUs is always at 100% usage. Can anyone tell what the problem is from the pictures?

System Monitor resources view

Processes showing no serious CPU usage

System Monitor showing 100% CPU usage and switching to another CPU

Thanks

2
  • I've seen this happen after a blanket font change in an old copy of Librewriter. What version system/Libre office are you running?
    – ubfan1
    Mar 20, 2018 at 3:10
  • 2
    Could you please edit your question to include the output of ps auxk -pcpu | head? Thanks. Mar 20, 2018 at 4:16

1 Answer 1

1

This happened to me today:

one cpu at 100 percent.png

From conky display the process ID is 14633, so in the terminal use:

───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~/Python$ ps -o ppid=14633
14633
17412
 3140
[1]+  Done                    gedit gmail-list-msg.py
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~/Python$ ps -s -p 14633
  UID   PID          PENDING          BLOCKED          IGNORED           CAUGHT STAT TTY        TIME COMMAND
    0 14633 0000000000000000 0000000000000000 ffffffffffffffff 0000000000000000 R    ?          9:16 [kworker/4:0]
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~/Python$ ps -s -p 3140
  UID   PID          PENDING          BLOCKED          IGNORED           CAUGHT STAT TTY        TIME COMMAND
 1000  3140 0000000000000000 0000000000000000 0000000000001000 0000000180010000 Sl   ?          0:07 /usr/lib/gnome
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~/Python$ ps -s -p 17412
  UID   PID          PENDING          BLOCKED          IGNORED           CAUGHT STAT TTY        TIME COMMAND
 1000 17412 0000000000000000 0000000000010000 0000000000380004 000000004b817efb Ss   pts/19     0:00 bash
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~/Python$ 

The 100% CPU usage was caused by using:

gedit gmail-list.msg.py &

gedit is used all the time as a background process and this is the first time I've seen 100% usage.

  • After closing gedit the offending process: kworker/4:0 is still using 100% of one CPU.
  • After closing gnome-terminal the offending process is still using 100% of one CPU.
  • After opening a new terminal using sudo kill 14633 doesn't help.
  • After using sudo kill 3140 there is no change.
  • Using sudo kill 17412 has no effect.

The only option left is to reboot and monitor if using gedit Xxxx & causes problem to reoccur.


First Reboot

After first reboot the problem shifted from CPU 4 to CPU 0 and offending kworker changed from 4 to 3.

Gnome terminal was automatically called by Startup Applications which seemed a regression of this bug: Debian Bug report logs - #594245 gnome-terminal using a lot of cpu

I deactivated gnome-terminal from Startup Applications and rebooted


Second Reboot

After second reboot no CPU is running at 100%.

I notice another problem where CPU frequency is running close to maximum of 3,000 MHz when it should be around 1,000 MHz with powersave governor active (which it is).

I also notice a crash report on pstree which is called by one of my bash script daemons that didn't wake up properly. I filed the automatic data collection bug report with Ubuntu and then rebooted.


Third Reboot

The BIOS start up screen seems frozen. Do a 1 second power button press and it acts like a 10 second power button press (hard power off).

Press power button again for cold boot (no longer a Restart / Warm Boot).


Power up after Shutdown

All is well again. Unknown what exactly went wrong but hopefully the documented steps helps others diagnose transient errors.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.