• [6.8.0 RC1] CPU Percentage Difference Between Power Save & Performance


    Taddeusz
    • Annoyance

    I have an i5 8400 which I had previously set the scaling governor to Power Save. Recently I changed it to Performance and noticed that my CPU's normal idle usage is much lower. I also noticed on Performance governor my CPU seems to be pegged at the 6-core turbo frequency of 3.8Ghz rather than doing any scaling, which I'm not entirely certain is a bug or not. 6.7 would still scale the CPU on Performance but not quite as aggressively as Power Save. Maybe this is a change in the scaling driver. Idle temps have only risen about 4-6C. I'm ok with that change. Just something else I noticed.

     

    I don't know how the dashboard calculates CPU usage but it seems like it has something to do with the CPU frequency.




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    I'm not sure how Tips and Tweaks adjusted it before but I might see the CPU frequency scaling difference. In Performance the energy_performance_preference is also being set to "performance". On Power Save it is set to "balance_performance". I'm guessing the performance energy preference essentially disables all scaling.

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    1 hour ago, Taddeusz said:

    I'm not sure how Tips and Tweaks adjusted it before but I might see the CPU frequency scaling difference. In Performance the energy_performance_preference is also being set to "performance". On Power Save it is set to "balance_performance". I'm guessing the performance energy preference essentially disables all scaling.

    Quote

     

    performance  Run the CPU at the maximum frequency.

    powersave  Run the CPU at the minimum frequency.

    userspace  Run the CPU at user specified frequencies.

    ondemand  Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly back off as the idle time increases.

    conservative  Scales the frequency dynamically according to current load. Scales the frequency more gradually than ondemand.

    schedutil  Scheduler-driven CPU frequency selection [1], [2].

     

     

    Quote

    I don't know how the dashboard calculates CPU usage but it seems like it has something to do with the CPU frequency.

    It doesn't.  Only what the kernel reports as usage

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