| Message ID | 20231221152407.436177-1-vincent.guittot@linaro.org |
|---|---|
| Headers | show |
| Series | Rework system pressure interface to the scheduler | expand |
On Thu, Dec 21, 2023 at 4:24 PM Vincent Guittot <vincent.guittot@linaro.org> wrote: > > Provide to the scheduler a feedback about the temporary max available > capacity. Unlike arch_update_thermal_pressure, this doesn't need to be > filtered as the pressure will happen for dozens ms or more. > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++++++++++++++++++++ > include/linux/cpufreq.h | 10 ++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 44db4f59c4cc..15bd41f9bb5e 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2563,6 +2563,38 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) > } > EXPORT_SYMBOL(cpufreq_get_policy); > > +DEFINE_PER_CPU(unsigned long, cpufreq_pressure); > + > +/** > + * cpufreq_update_pressure() - Update cpufreq pressure for CPUs > + * @policy: cpufreq policy of the CPUs. > + * > + * Update the value of cpufreq pressure for all @cpus in the policy. > + */ > +static void cpufreq_update_pressure(struct cpufreq_policy *policy) > +{ > + unsigned long max_capacity, capped_freq, pressure; > + u32 max_freq; > + int cpu; > + > + cpu = cpumask_first(policy->related_cpus); > + pressure = max_capacity = arch_scale_cpu_capacity(cpu); I would prefer two separate statements instead of the above. Other than this Acked-by: Rafael J. Wysocki <rafael@kernel.org> > + capped_freq = policy->max; > + max_freq = arch_scale_freq_ref(cpu); > + > + /* > + * Handle properly the boost frequencies, which should simply clean > + * the thermal pressure value. > + */ > + if (max_freq <= capped_freq) > + pressure -= max_capacity; > + else > + pressure -= mult_frac(max_capacity, capped_freq, max_freq); > + > + for_each_cpu(cpu, policy->related_cpus) > + WRITE_ONCE(per_cpu(cpufreq_pressure, cpu), pressure); > +} > + > /** > * cpufreq_set_policy - Modify cpufreq policy parameters. > * @policy: Policy object to modify. > @@ -2618,6 +2650,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, > policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H); > trace_cpu_frequency_limits(policy); > > + cpufreq_update_pressure(policy); > + > policy->cached_target_freq = UINT_MAX; > > pr_debug("new min and max freqs are %u - %u kHz\n", > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index afda5f24d3dd..b1d97edd3253 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -241,6 +241,12 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy); > void cpufreq_enable_fast_switch(struct cpufreq_policy *policy); > void cpufreq_disable_fast_switch(struct cpufreq_policy *policy); > bool has_target_index(void); > + > +DECLARE_PER_CPU(unsigned long, cpufreq_pressure); > +static inline unsigned long cpufreq_get_pressure(int cpu) > +{ > + return per_cpu(cpufreq_pressure, cpu); > +} > #else > static inline unsigned int cpufreq_get(unsigned int cpu) > { > @@ -263,6 +269,10 @@ static inline bool cpufreq_supports_freq_invariance(void) > return false; > } > static inline void disable_cpufreq(void) { } > +static inline unsigned long cpufreq_get_pressure(int cpu) > +{ > + return 0; > +} > #endif > > #ifdef CONFIG_CPU_FREQ_STAT > -- > 2.34.1 >
On Thu, Dec 21, 2023 at 8:57 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Thu, Dec 21, 2023 at 4:24 PM Vincent Guittot > <vincent.guittot@linaro.org> wrote: > > > > Provide to the scheduler a feedback about the temporary max available > > capacity. Unlike arch_update_thermal_pressure, this doesn't need to be > > filtered as the pressure will happen for dozens ms or more. > > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > > --- > > drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++++++++++++++++++++ > > include/linux/cpufreq.h | 10 ++++++++++ > > 2 files changed, 44 insertions(+) > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > index 44db4f59c4cc..15bd41f9bb5e 100644 > > --- a/drivers/cpufreq/cpufreq.c > > +++ b/drivers/cpufreq/cpufreq.c > > @@ -2563,6 +2563,38 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) > > } > > EXPORT_SYMBOL(cpufreq_get_policy); > > > > +DEFINE_PER_CPU(unsigned long, cpufreq_pressure); > > + > > +/** > > + * cpufreq_update_pressure() - Update cpufreq pressure for CPUs > > + * @policy: cpufreq policy of the CPUs. > > + * > > + * Update the value of cpufreq pressure for all @cpus in the policy. > > + */ > > +static void cpufreq_update_pressure(struct cpufreq_policy *policy) > > +{ > > + unsigned long max_capacity, capped_freq, pressure; > > + u32 max_freq; > > + int cpu; > > + > > + cpu = cpumask_first(policy->related_cpus); > > + pressure = max_capacity = arch_scale_cpu_capacity(cpu); > > I would prefer two separate statements instead of the above. > > Other than this > > Acked-by: Rafael J. Wysocki <rafael@kernel.org> > > > + capped_freq = policy->max; > > + max_freq = arch_scale_freq_ref(cpu); > > + > > + /* > > + * Handle properly the boost frequencies, which should simply clean > > + * the thermal pressure value. > > + */ > > + if (max_freq <= capped_freq) > > + pressure -= max_capacity; Actually, it would be somewhat cleaner to do pressure = 0; here and > > + else > > + pressure -= mult_frac(max_capacity, capped_freq, max_freq); pressure = max_capacity - mult_frac(max_capacity, capped_freq, max_freq); and it would not be necessary to initialize pressure. > > + > > + for_each_cpu(cpu, policy->related_cpus) > > + WRITE_ONCE(per_cpu(cpufreq_pressure, cpu), pressure); > > +} > > + > > /** > > * cpufreq_set_policy - Modify cpufreq policy parameters. > > * @policy: Policy object to modify. > > @@ -2618,6 +2650,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, > > policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H); > > trace_cpu_frequency_limits(policy); > > > > + cpufreq_update_pressure(policy); > > + > > policy->cached_target_freq = UINT_MAX; > > > > pr_debug("new min and max freqs are %u - %u kHz\n", > > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > > index afda5f24d3dd..b1d97edd3253 100644 > > --- a/include/linux/cpufreq.h > > +++ b/include/linux/cpufreq.h > > @@ -241,6 +241,12 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy); > > void cpufreq_enable_fast_switch(struct cpufreq_policy *policy); > > void cpufreq_disable_fast_switch(struct cpufreq_policy *policy); > > bool has_target_index(void); > > + > > +DECLARE_PER_CPU(unsigned long, cpufreq_pressure); > > +static inline unsigned long cpufreq_get_pressure(int cpu) > > +{ > > + return per_cpu(cpufreq_pressure, cpu); > > +} > > #else > > static inline unsigned int cpufreq_get(unsigned int cpu) > > { > > @@ -263,6 +269,10 @@ static inline bool cpufreq_supports_freq_invariance(void) > > return false; > > } > > static inline void disable_cpufreq(void) { } > > +static inline unsigned long cpufreq_get_pressure(int cpu) > > +{ > > + return 0; > > +} > > #endif > > > > #ifdef CONFIG_CPU_FREQ_STAT > > -- > > 2.34.1 > >
Following the consolidation and cleanup of CPU capacity in [1], this serie reworks how the scheduler gets the pressures on CPUs. We need to take into account all pressures applied by cpufreq on the compute capacity of a CPU for dozens of ms or more and not only cpufreq cooling device or HW mitigiations. we split the pressure applied on CPU's capacity in 2 parts: - one from cpufreq and freq_qos - one from HW high freq mitigiation. The next step will be to add a dedicated interface for long standing capping of the CPU capacity (i.e. for seconds or more) like the scaling_max_freq of cpufreq sysfs. The latter is already taken into account by this serie but as a temporary pressure which is not always the best choice when we know that it will happen for seconds or more. [1] https://lore.kernel.org/lkml/20231211104855.558096-1-vincent.guittot@linaro.org/ Change since v1: - Use struct cpufreq_policy as parameter of cpufreq_update_pressure() - Fix typos and comments - Make sched_thermal_decay_shift boot param as deprecated Vincent Guittot (5): cpufreq: Add a cpufreq pressure feedback for the scheduler sched: Take cpufreq feedback into account thermal/cpufreq: Remove arch_update_thermal_pressure() sched: Rename arch_update_thermal_pressure into arch_update_hw_pressure sched/pelt: Remove shift of thermal clock .../admin-guide/kernel-parameters.txt | 1 + arch/arm/include/asm/topology.h | 6 +- arch/arm64/include/asm/topology.h | 6 +- drivers/base/arch_topology.c | 26 ++++---- drivers/cpufreq/cpufreq.c | 34 ++++++++++ drivers/cpufreq/qcom-cpufreq-hw.c | 4 +- drivers/thermal/cpufreq_cooling.c | 3 - include/linux/arch_topology.h | 8 +-- include/linux/cpufreq.h | 10 +++ include/linux/sched/topology.h | 8 +-- .../{thermal_pressure.h => hw_pressure.h} | 14 ++--- include/trace/events/sched.h | 2 +- init/Kconfig | 12 ++-- kernel/sched/core.c | 8 +-- kernel/sched/fair.c | 63 +++++++++---------- kernel/sched/pelt.c | 18 +++--- kernel/sched/pelt.h | 16 ++--- kernel/sched/sched.h | 22 +------ 18 files changed, 142 insertions(+), 119 deletions(-) rename include/trace/events/{thermal_pressure.h => hw_pressure.h} (55%)