Messages in this thread Patch in this message | | | Subject | Re: [Patch v4 5/6] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping | From | Dietmar Eggemann <> | Date | Thu, 31 Oct 2019 17:29:46 +0100 |
| |
On 22.10.19 22:34, Thara Gopinath wrote: > Thermal governors can request for a cpu's maximum supported frequency > to be capped in case of an overheat event. This in turn means that the > maximum capacity available for tasks to run on the particular cpu is > reduced. Delta between the original maximum capacity and capped > maximum capacity is known as thermal pressure. Enable cpufreq cooling > device to update the thermal pressure in event of a capped > maximum frequency. > > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org> > --- > drivers/thermal/cpu_cooling.c | 31 +++++++++++++++++++++++++++++-- > 1 file changed, 29 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c > index 391f397..2e6a979 100644 > --- a/drivers/thermal/cpu_cooling.c > +++ b/drivers/thermal/cpu_cooling.c > @@ -218,6 +218,23 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev, > } > > /** > + * update_sched_max_capacity - update scheduler about change in cpu > + * max frequency. > + * @policy - cpufreq policy whose max frequency is capped. > + */ > +static void update_sched_max_capacity(struct cpumask *cpus, > + unsigned int cur_max_freq, > + unsigned int max_freq) > +{ > + int cpu; > + unsigned long capacity = (cur_max_freq << SCHED_CAPACITY_SHIFT) / > + max_freq; > + > + for_each_cpu(cpu, cpus) > + update_thermal_pressure(cpu, capacity); > +} > + > +/** > * get_load() - get load for a cpu since last updated > * @cpufreq_cdev: &struct cpufreq_cooling_device for this cpu > * @cpu: cpu number > @@ -320,6 +337,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > unsigned long state) > { > struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata; > + int ret; > > /* Request state should be less than max_level */ > if (WARN_ON(state > cpufreq_cdev->max_level)) > @@ -331,8 +349,17 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > > cpufreq_cdev->cpufreq_state = state; > > - return dev_pm_qos_update_request(&cpufreq_cdev->qos_req, > - cpufreq_cdev->freq_table[state].frequency); > + ret = dev_pm_qos_update_request > + (&cpufreq_cdev->qos_req, > + cpufreq_cdev->freq_table[state].frequency); > + > + if (ret > 0) > + update_sched_max_capacity > + (cpufreq_cdev->policy->cpus, > + cpufreq_cdev->freq_table[state].frequency, > + cpufreq_cdev->policy->cpuinfo.max_freq); > + > + return ret; > } > > /** >
Why not getting rid of update_sched_max_capacity() entirely and call update_thermal_pressure() in cpu_cooling.c directly? Saves one level in the call chain and would mean less code for this feature.
Just compile tested on arm64:
diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c index 3211b4d3a899..bf36995013b0 100644 --- a/drivers/thermal/cpu_cooling.c +++ b/drivers/thermal/cpu_cooling.c @@ -217,23 +217,6 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev, return freq_table[i - 1].frequency; }
-/** - * update_sched_max_capacity - update scheduler about change in cpu - * max frequency. - * @policy - cpufreq policy whose max frequency is capped. - */ -static void update_sched_max_capacity(struct cpumask *cpus, - unsigned int cur_max_freq, - unsigned int max_freq) -{ - int cpu; - unsigned long capacity = (cur_max_freq << SCHED_CAPACITY_SHIFT) / - max_freq; - - for_each_cpu(cpu, cpus) - update_thermal_pressure(cpu, capacity); -} - /** * get_load() - get load for a cpu since last updated * @cpufreq_cdev: &struct cpufreq_cooling_device for this cpu @@ -353,7 +336,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, cpufreq_cdev->freq_table[state].frequency);
if (ret > 0) - update_sched_max_capacity + update_thermal_pressure (cpufreq_cdev->policy->cpus, cpufreq_cdev->freq_table[state].frequency, cpufreq_cdev->policy->cpuinfo.max_freq); diff --git a/include/linux/sched.h b/include/linux/sched.h index 55dfe9634f67..5707813c7621 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1985,9 +1985,9 @@ static inline void rseq_syscall(struct pt_regs *regs) #endif
#ifdef CONFIG_SMP -void update_thermal_pressure(int cpu, u64 capacity); +void update_thermal_pressure(struct cpumask *cpus, unsigned int cur, unsigned int max); #else -static inline void update_thermal_pressure(int cpu, u64 capacity) +static inline void update_thermal_pressure(struct cpumask *cpus, unsigned int cur, unsigned int max); { } #endif diff --git a/kernel/sched/thermal.c b/kernel/sched/thermal.c index 0da31e12a5ff..691bdd79597a 100644 --- a/kernel/sched/thermal.c +++ b/kernel/sched/thermal.c @@ -43,17 +43,16 @@ static DEFINE_PER_CPU(unsigned long, delta_capacity); * the arch_scale_cpu_capacity and capped capacity is stored in per cpu * delta_capacity. */ -void update_thermal_pressure(int cpu, u64 capped_freq_ratio) +void update_thermal_pressure(struct cpumask *cpus, unsigned int cur, unsigned int max) { - unsigned long __capacity, delta; + int cpu;
- /* Normalize the capped freq ratio */ - __capacity = (capped_freq_ratio * arch_scale_cpu_capacity(cpu)) >> - SCHED_CAPACITY_SHIFT; - delta = arch_scale_cpu_capacity(cpu) - __capacity; - pr_debug("updating cpu%d thermal pressure to %lu\n", cpu, delta); + for_each_cpu(cpu, cpus) { + unsigned long scale_cap = arch_scale_cpu_capacity(cpu); + unsigned long cur_cap = cur * scale_cap / max;
- per_cpu(delta_capacity, cpu) = delta; + per_cpu(delta_capacity, cpu) = scale_cap - cur_cap; + } }
| |