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My i386 Lubuntu install is running with a constantly 100% CPU. Using top I have diagnosed "%id" as using up a lot of CPU, usually between about 50% and 99%. Why is this happening, and how can I stop it?

squirl
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    What is "id" doing. Can you [strace](http://linux.die.net/man/1/strace) it ? – Hennes Sep 03 '13 at 10:57
  • Sorry, I should have said "%id". Will edit now! – squirl Sep 03 '13 at 11:20
  • That is a surprising name for a process. Can you post a screenshot of the output of `top` (pressing `c` so that `top` shows the full command line)? Maybe you can also post the output of `ps auxww |head` and/or `pstree`. – sergut Sep 03 '13 at 14:28
  • On what basis do you think it is running with 100% cpu? As Frederik Deweerdt said, %id is "idle" (and therefore when it is 99% your cpu usage is 1%). Are you adding up the percentages and assuming that adding up to 100 means you're at 100%? – Random832 Sep 03 '13 at 16:24
  • @Random832, my lxpanel resource monitor shows full CPU all the time. – squirl Sep 04 '13 at 08:51

2 Answers2

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It sounds like you're misunderstanding top's output. %id is the amount of time the CPU has been idle, that is, doing nothing.

Frederik Deweerdt
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  • Ok, I understand. But then why does my resource monitor on my lxpanel show full CPU all the time? – squirl Sep 04 '13 at 08:49
  • Can you copy the first ten lines of top's output and paste it here? – Frederik Deweerdt Sep 04 '13 at 16:37
  • not quite 10 lines (too long for a comment), but here you are: top - 11:55:58 up 1:01, 5 users, load average: 0.41, 0.51, 0.53 Tasks: 124 total, 1 running, 123 sleeping, 0 stopped, 0 zombie %Cpu(s): 21.4 us, 5.6 sy, 0.0 ni, 68.7 id, 4.3 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 506964 total, 498164 used, 8800 free, 9148 buffers KiB Swap: 520188 total, 9644 used, 510544 free, 110392 cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 980 root 20 0 123m 33m 5112 S 10.6 6.8 3:19.83 Xorg – squirl Sep 05 '13 at 10:59
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    What you pasted shows: 21.4% usage by user space, 5.6% by the kernel, 4.3% in waiting for IO, and the rest (68.7) idle. It also shows the first process using memory, in this case Xorg,that uses 10.6% cpu. – Frederik Deweerdt Sep 05 '13 at 14:25
  • Turns out I have answered my own question, but thanks for the input! – squirl Sep 08 '13 at 11:19
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Ok, it turns out there is a problem with the resource monitor applet on my computer that means it shows full CPU all the time.

The fix? Use a resource monitor for RAM usage, and a CPU usage monitor for CPU usage.

squirl
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