Re: Pressing the power button causes the device to freeze completely (schedutil involved)

[Evgeny Sagatov]

> I guess you mean with the powersave governor.

That's the thing, I get these weird values in powersave mode.

> I would expect schedutil, ondemand and performance to give similar
> scores, but for powersave I would expect the score to be lower.

I did some measurements earlier. I got roughly the same values in
schedutil and performance modes. In ondemand mode, it was 7% lower. In
powersave mode, it was significantly lower, but I don't remember the
exact values.
Now, the values are at their maximum in all modes.

I see that the frequencies change frequently.

cat /proc/cpuinfo | grep MHz
cpu MHz         : 2000.000
cpu MHz         : 2000.000
cpu MHz         : 2673.037
cpu MHz         : 2601.029

But I don't see this reflected in the statistics.

grep -r . /sys/devices/system/cpu/cpufreq/
/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:2000000
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors:powersave
performance schedutil
/sys/devices/system/cpu/cpufreq/policy0/freqdomain_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq:2834000
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies:2834000
2000000
/sys/devices/system/cpu/cpufreq/policy0/related_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq:2000000
/sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed:<unsupported>
grep: /sys/devices/system/cpu/cpufreq/policy0/stats/reset: Access denied
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:   From  :    To
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:         :
2834000   2000000
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:  2834000:
      0         0
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:  2000000:
      0         0
/sys/devices/system/cpu/cpufreq/policy0/stats/total_trans:0
/sys/devices/system/cpu/cpufreq/policy0/stats/time_in_state:2834000 0
/sys/devices/system/cpu/cpufreq/policy0/stats/time_in_state:2000000 8222
/sys/devices/system/cpu/cpufreq/policy0/affected_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:2834000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency:160000
/sys/devices/system/cpu/cpufreq/policy0/scaling_driver:acpi-cpufreq
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq:2000000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_avg_freq:2000000
/sys/devices/system/cpu/cpufreq/policy0/bios_limit:2834000

grep . /sys/firmware/acpi/interrupts/sci*
/sys/firmware/acpi/interrupts/sci:       0
/sys/firmware/acpi/interrupts/sci_not:       0


I tried this with the previous patch, and the kernel didn't freeze
when I pressed the button.
But with kernel 6.12.74, it doesn't work.
echo 100000 > /sys/devices/system/cpu/cpufreq/schedutil/rate_limit_us

чт, 30 апр. 2026 г. в 17:10, Rafael J. Wysocki <rafael@xxxxxxxxxx>:
>
> On Thu, Apr 30, 2026 at 1:58 PM Evgeny Sagatov <evgeny.sagatov@xxxxxxxxx> wrote:
> >
> > I forgot to say that in ondemand mode, when I pressed the power
> > button, the PC did not freeze.
>
> OK
>
> I think that's because ondemand changes the CPU frequency 10 times
> less frequently than schedutil.
>
> Writing a sufficiently large number to
>
> /sys/devices/system/cpu/cpufreq/schedutil/rate_limit_us
>
> when schedutil is the cpufreq governor may help, but I actually don't
> know how large that number would need to be.