| Message ID | 1431396795-32439-2-git-send-email-mturquette@linaro.org (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Monday, May 11, 2015 07:13:12 PM Michael Turquette wrote: > From: Morten Rasmussen <Morten.Rasmussen@arm.com> > > Implements arch-specific function to provide the scheduler with a > frequency scaling correction factor for more accurate load-tracking. The > factor is: > > current_freq(cpu) << SCHED_CAPACITY_SHIFT / max_freq(cpu) > > This implementation only provides frequency invariance. No > micro-architecture invariance yet. > > Cc: Russell King <linux@arm.linux.org.uk> > Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> > --- > Changes in v2: > none > > arch/arm/include/asm/topology.h | 7 ++++++ > arch/arm/kernel/smp.c | 53 +++++++++++++++++++++++++++++++++++++++-- > arch/arm/kernel/topology.c | 17 +++++++++++++ > 3 files changed, 75 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h > index 2fe85ff..4b985dc 100644 > --- a/arch/arm/include/asm/topology.h > +++ b/arch/arm/include/asm/topology.h > @@ -24,6 +24,13 @@ void init_cpu_topology(void); > void store_cpu_topology(unsigned int cpuid); > const struct cpumask *cpu_coregroup_mask(int cpu); > > +#define arch_scale_freq_capacity arm_arch_scale_freq_capacity > +struct sched_domain; > +extern > +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu); > + > +DECLARE_PER_CPU(atomic_long_t, cpu_freq_capacity); > + > #else > > static inline void init_cpu_topology(void) { } > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 86ef244..297ce1b 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -672,12 +672,34 @@ static DEFINE_PER_CPU(unsigned long, l_p_j_ref); > static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); > static unsigned long global_l_p_j_ref; > static unsigned long global_l_p_j_ref_freq; > +static DEFINE_PER_CPU(atomic_long_t, cpu_max_freq); > +DEFINE_PER_CPU(atomic_long_t, cpu_freq_capacity); > + > +/* > + * Scheduler load-tracking scale-invariance > + * > + * Provides the scheduler with a scale-invariance correction factor that > + * compensates for frequency scaling through arch_scale_freq_capacity() > + * (implemented in topology.c). > + */ > +static inline > +void scale_freq_capacity(int cpu, unsigned long curr, unsigned long max) > +{ > + unsigned long capacity; > + > + if (!max) > + return; > + > + capacity = (curr << SCHED_CAPACITY_SHIFT) / max; > + atomic_long_set(&per_cpu(cpu_freq_capacity, cpu), capacity); > +} > > static int cpufreq_callback(struct notifier_block *nb, > unsigned long val, void *data) > { > struct cpufreq_freqs *freq = data; > int cpu = freq->cpu; > + unsigned long max = atomic_long_read(&per_cpu(cpu_max_freq, cpu)); > > if (freq->flags & CPUFREQ_CONST_LOOPS) > return NOTIFY_OK; > @@ -702,6 +724,9 @@ static int cpufreq_callback(struct notifier_block *nb, > per_cpu(l_p_j_ref_freq, cpu), > freq->new); > } > + > + scale_freq_capacity(cpu, freq->new, max); > + > return NOTIFY_OK; > } > > @@ -709,11 +734,35 @@ static struct notifier_block cpufreq_notifier = { > .notifier_call = cpufreq_callback, > }; > > +static int cpufreq_policy_callback(struct notifier_block *nb, > + unsigned long val, void *data) > +{ > + struct cpufreq_policy *policy = data; > + int i; > + > + for_each_cpu(i, policy->cpus) { > + scale_freq_capacity(i, policy->cur, policy->max); > + atomic_long_set(&per_cpu(cpu_max_freq, i), policy->max); > + } > + > + return NOTIFY_OK; > +} > + > +static struct notifier_block cpufreq_policy_notifier = { > + .notifier_call = cpufreq_policy_callback, > +}; > + > static int __init register_cpufreq_notifier(void) > { > - return cpufreq_register_notifier(&cpufreq_notifier, > + int ret; > + > + ret = cpufreq_register_notifier(&cpufreq_notifier, > CPUFREQ_TRANSITION_NOTIFIER); > + if (ret) > + return ret; > + > + return cpufreq_register_notifier(&cpufreq_policy_notifier, > + CPUFREQ_POLICY_NOTIFIER); > } > core_initcall(register_cpufreq_notifier); > - > #endif > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c > index 08b7847..9c09e6e 100644 > --- a/arch/arm/kernel/topology.c > +++ b/arch/arm/kernel/topology.c > @@ -169,6 +169,23 @@ static void update_cpu_capacity(unsigned int cpu) > cpu, arch_scale_cpu_capacity(NULL, cpu)); > } > > +/* > + * Scheduler load-tracking scale-invariance > + * > + * Provides the scheduler with a scale-invariance correction factor that > + * compensates for frequency scaling (arch_scale_freq_capacity()). The scaling > + * factor is updated in smp.c > + */ > +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu) > +{ > + unsigned long curr = atomic_long_read(&per_cpu(cpu_freq_capacity, cpu)); > + > + if (!curr) > + return SCHED_CAPACITY_SCALE; > + > + return curr; > +} > + > #else > static inline void parse_dt_topology(void) {} > static inline void update_cpu_capacity(unsigned int cpuid) {} I'm not sure if I'm reading this correctly, but what exactly is ARM-specific in this new code? Could it be made generic, in particular?
diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h index 2fe85ff..4b985dc 100644 --- a/arch/arm/include/asm/topology.h +++ b/arch/arm/include/asm/topology.h @@ -24,6 +24,13 @@ void init_cpu_topology(void); void store_cpu_topology(unsigned int cpuid); const struct cpumask *cpu_coregroup_mask(int cpu); +#define arch_scale_freq_capacity arm_arch_scale_freq_capacity +struct sched_domain; +extern +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu); + +DECLARE_PER_CPU(atomic_long_t, cpu_freq_capacity); + #else static inline void init_cpu_topology(void) { } diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 86ef244..297ce1b 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -672,12 +672,34 @@ static DEFINE_PER_CPU(unsigned long, l_p_j_ref); static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); static unsigned long global_l_p_j_ref; static unsigned long global_l_p_j_ref_freq; +static DEFINE_PER_CPU(atomic_long_t, cpu_max_freq); +DEFINE_PER_CPU(atomic_long_t, cpu_freq_capacity); + +/* + * Scheduler load-tracking scale-invariance + * + * Provides the scheduler with a scale-invariance correction factor that + * compensates for frequency scaling through arch_scale_freq_capacity() + * (implemented in topology.c). + */ +static inline +void scale_freq_capacity(int cpu, unsigned long curr, unsigned long max) +{ + unsigned long capacity; + + if (!max) + return; + + capacity = (curr << SCHED_CAPACITY_SHIFT) / max; + atomic_long_set(&per_cpu(cpu_freq_capacity, cpu), capacity); +} static int cpufreq_callback(struct notifier_block *nb, unsigned long val, void *data) { struct cpufreq_freqs *freq = data; int cpu = freq->cpu; + unsigned long max = atomic_long_read(&per_cpu(cpu_max_freq, cpu)); if (freq->flags & CPUFREQ_CONST_LOOPS) return NOTIFY_OK; @@ -702,6 +724,9 @@ static int cpufreq_callback(struct notifier_block *nb, per_cpu(l_p_j_ref_freq, cpu), freq->new); } + + scale_freq_capacity(cpu, freq->new, max); + return NOTIFY_OK; } @@ -709,11 +734,35 @@ static struct notifier_block cpufreq_notifier = { .notifier_call = cpufreq_callback, }; +static int cpufreq_policy_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct cpufreq_policy *policy = data; + int i; + + for_each_cpu(i, policy->cpus) { + scale_freq_capacity(i, policy->cur, policy->max); + atomic_long_set(&per_cpu(cpu_max_freq, i), policy->max); + } + + return NOTIFY_OK; +} + +static struct notifier_block cpufreq_policy_notifier = { + .notifier_call = cpufreq_policy_callback, +}; + static int __init register_cpufreq_notifier(void) { - return cpufreq_register_notifier(&cpufreq_notifier, + int ret; + + ret = cpufreq_register_notifier(&cpufreq_notifier, CPUFREQ_TRANSITION_NOTIFIER); + if (ret) + return ret; + + return cpufreq_register_notifier(&cpufreq_policy_notifier, + CPUFREQ_POLICY_NOTIFIER); } core_initcall(register_cpufreq_notifier); - #endif diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index 08b7847..9c09e6e 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -169,6 +169,23 @@ static void update_cpu_capacity(unsigned int cpu) cpu, arch_scale_cpu_capacity(NULL, cpu)); } +/* + * Scheduler load-tracking scale-invariance + * + * Provides the scheduler with a scale-invariance correction factor that + * compensates for frequency scaling (arch_scale_freq_capacity()). The scaling + * factor is updated in smp.c + */ +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu) +{ + unsigned long curr = atomic_long_read(&per_cpu(cpu_freq_capacity, cpu)); + + if (!curr) + return SCHED_CAPACITY_SCALE; + + return curr; +} + #else static inline void parse_dt_topology(void) {} static inline void update_cpu_capacity(unsigned int cpuid) {}