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I'm using the i3 window manager on my Ubuntu box. According to /proc/cpuinfo, my machine has 20 processors. However, when I do a big parallel job (say, make -j), i3's status bar will often show a very high CPU usage figure (sometimes over 300).

How is this possible?

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    Is that a percentage of one CPU maybe? Or CPU load? It's difficult to say anything precise as you don't mention any units.
    – Kusalananda ♦
    Commented Jun 3, 2022 at 13:50
  • What i3status (the thing that normally - and I guess the OP would know if it was different - generates the stuff shown in i3's status bar is just the load, which is just the number of processes ready to run (technically: in R- or D-state), there's no limit to how high that number can be, and I've seen quite a bit above 300.
    – Henrik supports the community
    Commented Jun 3, 2022 at 13:58
  • man i3status describes it as "the percentual CPU usage".
    – Daniel Walker
    Commented Jun 3, 2022 at 14:02
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    @DanielWalker: I can see that in the man page, but that's not in the standard config, that shows load as I described.
    – Henrik supports the community
    Commented Jun 3, 2022 at 15:02
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    @Henriksupportsthecommunity load is not "just the number of processes ready to run", it's considerably more complicated. See How can I chose a max load threshold depending on the number of available cores?.
    – terdon ♦
    Commented Jun 3, 2022 at 15:03

2 Answers 2

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What i3status, the thing that normally generates the stuff shown in i3's status bar, is showing is just the load which is just the number of processes ready to run (technically: in R- or D-state). There's no limit to how high that number can be and I've seen quite a bit above 300.

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  • You can see which fields are which in /etc/i3status.conf. See here.
    – Daniel Walker
    Commented Jun 23, 2023 at 13:40
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When monitoring CPU usage like this, some software such as mpstat or i3status will consider 1 core's usage to be equal to 100% usage, so in your case, 300% would be equal to 3 cores, or more likely 3 threads depending on the thread count of your CPU.

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  • I don't think it's a percentage. According to htop, all 20 processors are at 100%.
    – Daniel Walker
    Commented Jun 4, 2022 at 2:19
  • Interesting. Perhaps try running a parallel job with a lower job count (like 5) and seeing what happens with i3status?
    – Slips
    Commented Jun 4, 2022 at 13:42

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