Messages in this thread | | | From | Vincent Guittot <> | Date | Sun, 11 Feb 2024 14:36:02 +0100 | Subject | Re: sched/cpufreq: Rework schedutil governor performance estimation - Regression bisected |
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On Sat, 10 Feb 2024 at 00:16, Doug Smythies <dsmythies@telus.net> wrote: > > Hi Vincent, > Thank you for your quick reply. > > On 2024.02.09.14:11 Vincent wrote: > On Fri, 9 Feb 2024 at 22:38, Doug Smythies <dsmythies@telus.net> wrote: > >> > >> Hi, > >> > >> I noticed a regression in the 6.8rc series kernels. Bisecting the kernel pointed to: > >> > >> # first bad commit: [9c0b4bb7f6303c9c4e2e34984c46f5a86478f84d] > >> sched/cpufreq: Rework schedutil governor performance estimation > >> > >> There was previous bisection and suggestion of reversion, > >> but I guess it wasn't done in the end. [1] > > > > This has been fixed with > > https://lore.kernel.org/all/170539970061.398.16662091173685476681.tip-bot2@tip-bot2/ > > Okay, thanks. I didn't find that one. > > >> The regression: reduced maximum CPU frequency is ignored. > > > This seems to be something new. > > schedutil doesn't impact the max_freq and it's up to cpufreq driver > > select the final freq which should stay within the limits > > Okay. All I know is this is the commit that caused the regression.
Could you check if the fix solved your problem ?
> I do not know why, but I do wonder if there could any relationship with > the old, never fixed, problem of incorrect stale frequencies reported > under the same operating conditions. See the V2 note: > https://lore.kernel.org/all/001d01d9d3a7$71736f50$545a4df0$@telus.net/
IIUC the problem is that policy->cur is not used by intel_cpufreq and stays set to the last old/init value. Do I get it right that this is only informative ?
Normally cpufreq governor checks the new limits and updates current freq if necessary except when fast switch is enabled.
> > where I haven't been able to figure out a solution. > > >> Conditions: > >> CPU frequency scaling driver: intel_cpufreq (a.k.a intel_pstate in passive mode) > >> CPU frequency scaling governor: schedutil > >> HWP (HardWare Pstate) control (a.k.a. Intel_speedshift): Enabled > >> Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz > >> > >> I did not check any other conditions, i.e. HWP disabled or the acpi-cpufreq driver. > >> > >> Example: A 100% load on CPU 5. > >> > >> sudo turbostat --quiet --Summary --show Busy%,Bzy_MHz,IRQ,PkgWatt,PkgTmp,RAMWatt,GFXWatt,CorWatt --interval 15 > >> Busy% Bzy_MHz IRQ PkgTmp PkgWatt CorWatt GFXWatt RAMWatt > >> 8.42 4636 21823 67 28.40 27.56 0.00 2.59 > >> 8.40 4577 17724 66 27.57 26.73 0.00 2.59 > >> 8.35 4637 19535 66 28.65 27.81 0.00 2.60 > >> 8.41 4578 20723 66 27.73 26.89 0.00 2.59 > >> 8.40 4558 19156 67 27.39 26.55 0.00 2.58 > >> 8.34 4502 18127 67 26.79 25.96 0.00 2.57 > >> > >> grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq > >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu10/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu11/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu2/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu3/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu6/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu8/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu9/cpufreq/scaling_max_freq:2400000 > >> > >> grep . /sys/devices/system/cpu/cpu5/cpufreq/* > >> /sys/devices/system/cpu/cpu5/cpufreq/affected_cpus:5 > >> /sys/devices/system/cpu/cpu5/cpufreq/base_frequency:4100000 > >> /sys/devices/system/cpu/cpu5/cpufreq/cpuinfo_max_freq:4800000 > >> /sys/devices/system/cpu/cpu5/cpufreq/cpuinfo_min_freq:800000 > >> /sys/devices/system/cpu/cpu5/cpufreq/cpuinfo_transition_latency:20000 > >> /sys/devices/system/cpu/cpu5/cpufreq/energy_performance_available_preferences:default performance balance_performance balance_power > >> power > >> /sys/devices/system/cpu/cpu5/cpufreq/energy_performance_preference:balance_performance > >> /sys/devices/system/cpu/cpu5/cpufreq/related_cpus:5 > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_available_governors:conservative ondemand userspace powersave performance schedutil > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_cur_freq:4799998 > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_driver:intel_cpufreq > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_governor:schedutil > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_max_freq:2400000 > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_min_freq:800000 > >> /sys/devices/system/cpu/cpu5/cpufreq/scaling_setspeed:<unsupported> > >> > >> [1] https://lore.kernel.org/all/CAKfTPtDCQuJjpi6=zjeWPcLeP+ZY5Dw7XDrZ-LpXqEAAUbXLhA@mail.gmail.com/ > >
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