On Thu, Aug 17, 2023 at 11:31 AM Sumit Gupta <sumitg@xxxxxxxxxx> wrote: > > From: Srikar Srimath Tirumala <srikars@xxxxxxxxxx> > > Add support to configure the CPUFREQ reduction percentage and set the > maximum number of throttling steps accordingly. Current implementation > of processor_thermal performs software throttling in fixed steps of > "20%" which can be too coarse for some platforms. Change that by adding > new config to provide the reduction percentage. > > Signed-off-by: Srikar Srimath Tirumala <srikars@xxxxxxxxxx> > Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx> > --- > drivers/acpi/Kconfig | 15 +++++++++++++++ > drivers/acpi/processor_thermal.c | 19 ++++++++++++++++--- > 2 files changed, 31 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig > index 00dd309b6682..287cf58defbf 100644 > --- a/drivers/acpi/Kconfig > +++ b/drivers/acpi/Kconfig > @@ -254,6 +254,21 @@ config ACPI_DOCK > config ACPI_CPU_FREQ_PSS > bool > > +config ACPI_CPU_FREQ_THERM_HAS_PARAMS > + bool "CPU frequency throttling control" > + depends on ACPI_PROCESSOR > + > +config ACPI_CPU_FREQ_THERM_MIN_THROT_PCTG > + int "Minimum throttle percentage for processor_thermal cooling device" > + depends on ACPI_CPU_FREQ_THERM_HAS_PARAMS > + default 20 > + help > + The processor_thermal driver uses this config to calculate the > + percentage amount by which cpu frequency must be reduced for each > + cooling state. The config is also used to calculate the maximum number > + of throttling steps or cooling states supported by the driver. Value > + must be an unsigned integer in the range [1, 50]. > + I don't think that the new Kconfig symbols are particularly useful. At least they don't help the distro vendors that each would need to pick up a specific value for their kernel anyway. I also wonder how the users building their own kernels are supposed to determine the values suitable for the target systems. > config ACPI_PROCESSOR_CSTATE > def_bool y > depends on ACPI_PROCESSOR > diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c > index b7c6287eccca..ee443cc69b73 100644 > --- a/drivers/acpi/processor_thermal.c > +++ b/drivers/acpi/processor_thermal.c > @@ -25,8 +25,20 @@ > * _any_ cpufreq driver and not only the acpi-cpufreq driver. > */ > > -#define CPUFREQ_THERMAL_MIN_STEP 0 > -#define CPUFREQ_THERMAL_MAX_STEP 3 > +#define CPUFREQ_THERMAL_MIN_STEP 0 > +#ifdef CONFIG_ACPI_CPU_FREQ_THERM_HAS_PARAMS > +#define CPUFREQ_THERMAL_PCTG CONFIG_ACPI_CPU_FREQ_THERM_MIN_THROT_PCTG > + > +/* Derive the MAX_STEP from minimum throttle percentage so that the reduction > + * percentage does end up becoming negative. Also cap the MAX_STEP so that > + * the CPU performance doesn't become 0. > + */ > +#define CPUFREQ_THERMAL_MAX_STEP ((100 / CPUFREQ_THERMAL_PCTG) - 1) > + > +#else > +#define CPUFREQ_THERMAL_MAX_STEP 3 > +#define CPUFREQ_THERMAL_PCTG 20 > +#endif > > static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg); > > @@ -113,7 +125,8 @@ static int cpufreq_set_cur_state(unsigned int cpu, int state) > if (!policy) > return -EINVAL; > > - max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100; > + max_freq = (policy->cpuinfo.max_freq * > + (100 - reduction_pctg(i) * CPUFREQ_THERMAL_PCTG)) / 100; > > cpufreq_cpu_put(policy); > > --
