Messages in this thread | | | Date | Fri, 6 Oct 2023 20:44:49 +0530 | Subject | Re: [Patch v2 2/2] ACPI: processor: reduce CPUFREQ thermal reduction pctg for Tegra241 | From | Sumit Gupta <> |
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On 04/10/23 01:07, Rafael J. Wysocki wrote: > External email: Use caution opening links or attachments > > > On Wed, Sep 13, 2023 at 6:47 PM Sumit Gupta <sumitg@nvidia.com> wrote: >> >> From: Srikar Srimath Tirumala <srikars@nvidia.com> >> >> Current implementation of processor_thermal performs software throttling >> in fixed steps of "20%" which can be too coarse for some platforms. >> We observed some performance gain after reducing the throttle percentage. >> Change the CPUFREQ thermal reduction percentage and maximum thermal steps >> to be configurable. Also, update the default values of both for Nvidia >> Tegra241 (Grace) SoC. The thermal reduction percentage is reduced to "5%" >> and accordingly the maximum number of thermal steps are increased as they >> are derived from the reduction percentage. >> >> Signed-off-by: Srikar Srimath Tirumala <srikars@nvidia.com> >> Signed-off-by: Sumit Gupta <sumitg@nvidia.com> >> --- >> drivers/acpi/processor_thermal.c | 41 +++++++++++++++++++++++++++++--- >> 1 file changed, 38 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c >> index b7c6287eccca..30f2801abce6 100644 >> --- a/drivers/acpi/processor_thermal.c >> +++ b/drivers/acpi/processor_thermal.c >> @@ -26,7 +26,16 @@ >> */ >> >> #define CPUFREQ_THERMAL_MIN_STEP 0 >> -#define CPUFREQ_THERMAL_MAX_STEP 3 >> + >> +static int cpufreq_thermal_max_step = 3; > > __read_mostly I suppose? >
Added in v3.
>> + >> +/* >> + * Minimum throttle percentage for processor_thermal cooling device. > > + * > >> + * The processor_thermal driver uses it to calculate the percentage amount by >> + * which cpu frequency must be reduced for each cooling state. This is also used >> + * to calculate the maximum number of throttling steps or cooling states. >> + */ >> +static int cpufreq_thermal_pctg = 20; > > __read_mostly here too? >
Added in v3.
>> >> static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg); >> >> @@ -71,7 +80,7 @@ static int cpufreq_get_max_state(unsigned int cpu) >> if (!cpu_has_cpufreq(cpu)) >> return 0; >> >> - return CPUFREQ_THERMAL_MAX_STEP; >> + return cpufreq_thermal_max_step; >> } >> >> static int cpufreq_get_cur_state(unsigned int cpu) >> @@ -113,7 +122,8 @@ 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); >> >> @@ -126,10 +136,35 @@ static int cpufreq_set_cur_state(unsigned int cpu, int state) >> return 0; >> } >> > > #ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY > >> +#define SMCCC_SOC_ID_T241 0x036b0241 >> + >> +void acpi_thermal_cpufreq_config_nvidia(void) > > static void ? >
Added in v3.
>> +{ >> +#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY >> + s32 soc_id = arm_smccc_get_soc_id_version(); >> + >> + /* Check JEP106 code for NVIDIA Tegra241 chip (036b:0241) */ >> + if ((soc_id < 0) || (soc_id != SMCCC_SOC_ID_T241)) > > Inner parens are redundant. >
Removed in v3.
>> + return; >> + >> + /* Reduce the CPUFREQ Thermal reduction percentage to 5% */ >> + cpufreq_thermal_pctg = 5; >> + >> + /* >> + * Derive the MAX_STEP from minimum throttle percentage so that the reduction >> + * percentage doesn't end up becoming negative. Also, cap the MAX_STEP so that >> + * the CPU performance doesn't become 0. >> + */ >> + cpufreq_thermal_max_step = ((100 / cpufreq_thermal_pctg) - 1); > > Outer parens are redundant. >
ACK.
>> +#endif >> +} > > #else > static inline void void acpi_thermal_cpufreq_config_nvidia(void) {} > #endif > >> + >> void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy) >> { >> unsigned int cpu; >> >> + acpi_thermal_cpufreq_config_nvidia(); >> + >> for_each_cpu(cpu, policy->related_cpus) { >> struct acpi_processor *pr = per_cpu(processors, cpu); >> int ret; >> -- > > And patch [1/2] needs to be rebased on the current ACPI thermal > material in linux-next. >
Ok.
> Thanks!
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