| Message ID | 20231018162540.667646-7-vincent.guittot@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,1/6] topology: add a new arch_scale_freq_reference | expand |
Hi, On Wednesday 18 Oct 2023 at 18:25:40 (+0200), Vincent Guittot wrote: > Use the new capacity_ref_freq to set the ratio that is used by AMU for > computing the arch_scale_freq_capacity(). > This helps to keep everything aligned using the same reference for > computing CPUs capacity. > > The default value of the ratio ensures that arch_scale_freq_capacity() > returns max capacity until it is set to its correct value with the > cpu capacity and capacity_ref_freq. > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > arch/arm64/kernel/topology.c | 18 ++++++++++-------- > drivers/base/arch_topology.c | 14 ++++++++++++-- > include/linux/arch_topology.h | 1 + > 3 files changed, 23 insertions(+), 10 deletions(-) > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index 817d788cd866..0f8f6e90c46d 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -82,7 +82,12 @@ int __init parse_acpi_topology(void) > #undef pr_fmt > #define pr_fmt(fmt) "AMU: " fmt > > -static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale); > +/* > + * Ensure that amu_scale_freq_tick() will return SCHED_CAPACITY_SHIFT until > + * the CPU capacity and its assosciated frequency have been correctly > + * initialized. s/SCHED_CAPACITY_SHIFT/SCHED_CAPACITY_SCALE > + */ > +static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale) = (2 * SCHED_CAPACITY_SHIFT); It should be 1UL << (2 * SCHED_CAPACITY_SHIFT). > static DEFINE_PER_CPU(u64, arch_const_cycles_prev); > static DEFINE_PER_CPU(u64, arch_core_cycles_prev); > static cpumask_var_t amu_fie_cpus; > @@ -112,9 +117,9 @@ static inline bool freq_counters_valid(int cpu) > return true; > } > > -static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) > +int freq_inv_set_max_ratio(int cpu, u64 max_rate) > { > - u64 ratio; > + u64 ratio, ref_rate = arch_timer_get_rate(); > > if (unlikely(!max_rate || !ref_rate)) { > pr_debug("CPU%d: invalid maximum or reference frequency.\n", > @@ -142,7 +147,7 @@ static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) > return -EINVAL; > } The return value is no longer used so it might be worth declaring it to return void and WARN_ONCE for unlikely(!max_rate || !ref_rate). > > - per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio; > + WRITE_ONCE(per_cpu(arch_max_freq_scale, cpu), (unsigned long)ratio); > > return 0; > } > @@ -195,10 +200,7 @@ static void amu_fie_setup(const struct cpumask *cpus) > return; > > for_each_cpu(cpu, cpus) { > - if (!freq_counters_valid(cpu) || > - freq_inv_set_max_ratio(cpu, > - cpufreq_get_hw_max_freq(cpu) * 1000ULL, > - arch_timer_get_rate())) > + if (!freq_counters_valid(cpu)) > return; > } > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index 2372ce791bb4..3a604b77b12d 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -344,6 +344,11 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) > return !ret; > } > > +int __weak freq_inv_set_max_ratio(int cpu, u64 max_rate) > +{ > + return 0; > +} > + > #ifdef CONFIG_ACPI_CPPC_LIB > #include <acpi/cppc_acpi.h> > > @@ -369,7 +374,6 @@ void topology_init_cpu_capacity_cppc(void) > capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]); > > per_cpu(capacity_ref_freq, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]); > - > pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n", > cpu, raw_capacity[cpu]); > continue; > @@ -381,6 +385,9 @@ void topology_init_cpu_capacity_cppc(void) > } > > for_each_possible_cpu(cpu) { > + freq_inv_set_max_ratio(cpu, > + per_cpu(capacity_ref_freq, cpu)); > + > capacity = raw_capacity[cpu]; > capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, > capacity_scale); > @@ -422,8 +429,11 @@ init_cpu_capacity_callback(struct notifier_block *nb, > > cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); > > - for_each_cpu(cpu, policy->related_cpus) > + for_each_cpu(cpu, policy->related_cpus) { > per_cpu(capacity_ref_freq, cpu) = policy->cpuinfo.max_freq; > + freq_inv_set_max_ratio(cpu, > + per_cpu(capacity_ref_freq, cpu)); capacity_ref_freq is in KHz while arch_timer_get_rate() is in Hz. One or the other needs to be scaled. The same in topology_init_cpu_capacity_cppc(). Thanks, Ionela. > + } > > if (cpumask_empty(cpus_to_visit)) { > topology_normalize_cpu_scale(); > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > index 38ca6c76af56..b6e95d763279 100644 > --- a/include/linux/arch_topology.h > +++ b/include/linux/arch_topology.h > @@ -99,6 +99,7 @@ void update_siblings_masks(unsigned int cpu); > void remove_cpu_topology(unsigned int cpuid); > void reset_cpu_topology(void); > int parse_acpi_topology(void); > +int freq_inv_set_max_ratio(int cpu, u64 max_rate); > #endif > > #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ > -- > 2.34.1 >
On Mon, 23 Oct 2023 at 22:58, Ionela Voinescu <ionela.voinescu@arm.com> wrote: > > Hi, > > On Wednesday 18 Oct 2023 at 18:25:40 (+0200), Vincent Guittot wrote: > > Use the new capacity_ref_freq to set the ratio that is used by AMU for > > computing the arch_scale_freq_capacity(). > > This helps to keep everything aligned using the same reference for > > computing CPUs capacity. > > > > The default value of the ratio ensures that arch_scale_freq_capacity() > > returns max capacity until it is set to its correct value with the > > cpu capacity and capacity_ref_freq. > > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > > --- > > arch/arm64/kernel/topology.c | 18 ++++++++++-------- > > drivers/base/arch_topology.c | 14 ++++++++++++-- > > include/linux/arch_topology.h | 1 + > > 3 files changed, 23 insertions(+), 10 deletions(-) > > > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > > index 817d788cd866..0f8f6e90c46d 100644 > > --- a/arch/arm64/kernel/topology.c > > +++ b/arch/arm64/kernel/topology.c > > @@ -82,7 +82,12 @@ int __init parse_acpi_topology(void) > > #undef pr_fmt > > #define pr_fmt(fmt) "AMU: " fmt > > > > -static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale); > > +/* > > + * Ensure that amu_scale_freq_tick() will return SCHED_CAPACITY_SHIFT until > > + * the CPU capacity and its assosciated frequency have been correctly > > + * initialized. > > s/SCHED_CAPACITY_SHIFT/SCHED_CAPACITY_SCALE > > > + */ > > +static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale) = (2 * SCHED_CAPACITY_SHIFT); > > It should be 1UL << (2 * SCHED_CAPACITY_SHIFT). yes > > > static DEFINE_PER_CPU(u64, arch_const_cycles_prev); > > static DEFINE_PER_CPU(u64, arch_core_cycles_prev); > > static cpumask_var_t amu_fie_cpus; > > @@ -112,9 +117,9 @@ static inline bool freq_counters_valid(int cpu) > > return true; > > } > > > > -static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) > > +int freq_inv_set_max_ratio(int cpu, u64 max_rate) > > { > > - u64 ratio; > > + u64 ratio, ref_rate = arch_timer_get_rate(); > > > > if (unlikely(!max_rate || !ref_rate)) { > > pr_debug("CPU%d: invalid maximum or reference frequency.\n", > > @@ -142,7 +147,7 @@ static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) > > return -EINVAL; > > } > > The return value is no longer used so it might be worth declaring it to > return void and WARN_ONCE for unlikely(!max_rate || !ref_rate). > > > > > - per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio; > > + WRITE_ONCE(per_cpu(arch_max_freq_scale, cpu), (unsigned long)ratio); > > > > return 0; > > } > > @@ -195,10 +200,7 @@ static void amu_fie_setup(const struct cpumask *cpus) > > return; > > > > for_each_cpu(cpu, cpus) { > > - if (!freq_counters_valid(cpu) || > > - freq_inv_set_max_ratio(cpu, > > - cpufreq_get_hw_max_freq(cpu) * 1000ULL, > > - arch_timer_get_rate())) > > + if (!freq_counters_valid(cpu)) > > return; > > } > > > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > > index 2372ce791bb4..3a604b77b12d 100644 > > --- a/drivers/base/arch_topology.c > > +++ b/drivers/base/arch_topology.c > > @@ -344,6 +344,11 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) > > return !ret; > > } > > > > +int __weak freq_inv_set_max_ratio(int cpu, u64 max_rate) > > +{ > > + return 0; > > +} > > + > > #ifdef CONFIG_ACPI_CPPC_LIB > > #include <acpi/cppc_acpi.h> > > > > @@ -369,7 +374,6 @@ void topology_init_cpu_capacity_cppc(void) > > capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]); > > > > per_cpu(capacity_ref_freq, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]); > > - > > pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n", > > cpu, raw_capacity[cpu]); > > continue; > > @@ -381,6 +385,9 @@ void topology_init_cpu_capacity_cppc(void) > > } > > > > for_each_possible_cpu(cpu) { > > + freq_inv_set_max_ratio(cpu, > > + per_cpu(capacity_ref_freq, cpu)); > > + > > capacity = raw_capacity[cpu]; > > capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, > > capacity_scale); > > @@ -422,8 +429,11 @@ init_cpu_capacity_callback(struct notifier_block *nb, > > > > cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); > > > > - for_each_cpu(cpu, policy->related_cpus) > > + for_each_cpu(cpu, policy->related_cpus) { > > per_cpu(capacity_ref_freq, cpu) = policy->cpuinfo.max_freq; > > + freq_inv_set_max_ratio(cpu, > > + per_cpu(capacity_ref_freq, cpu)); > > capacity_ref_freq is in KHz while arch_timer_get_rate() is in Hz. One or > the other needs to be scaled. > > The same in topology_init_cpu_capacity_cppc(). > > Thanks, > Ionela. > > > + } > > > > if (cpumask_empty(cpus_to_visit)) { > > topology_normalize_cpu_scale(); > > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > > index 38ca6c76af56..b6e95d763279 100644 > > --- a/include/linux/arch_topology.h > > +++ b/include/linux/arch_topology.h > > @@ -99,6 +99,7 @@ void update_siblings_masks(unsigned int cpu); > > void remove_cpu_topology(unsigned int cpuid); > > void reset_cpu_topology(void); > > int parse_acpi_topology(void); > > +int freq_inv_set_max_ratio(int cpu, u64 max_rate); > > #endif > > > > #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ > > -- > > 2.34.1 > >
On 24/10/2023 11:58, Vincent Guittot wrote: > On Mon, 23 Oct 2023 at 22:58, Ionela Voinescu <ionela.voinescu@arm.com> wrote: >> >> Hi, >> >> On Wednesday 18 Oct 2023 at 18:25:40 (+0200), Vincent Guittot wrote: >>> Use the new capacity_ref_freq to set the ratio that is used by AMU for >>> computing the arch_scale_freq_capacity(). >>> This helps to keep everything aligned using the same reference for >>> computing CPUs capacity. >>> >>> The default value of the ratio ensures that arch_scale_freq_capacity() >>> returns max capacity until it is set to its correct value with the >>> cpu capacity and capacity_ref_freq. Nitpick: Could you mention that arch_max_freq_scale is the default value for this ratio? Took me a while to recreate the (not so simple) story for this change, i.e. make the connection between ratio and arch_max_freq_scale. init_cpu_capacity_callback() freq_inv_set_max_ratio() u64 ratio ... per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio ^^^^^^^^^^^^^^^^^^^ static struct scale_freq_data amu_sfd = { .set_freq_scale = amu_scale_freq_tick, } #define arch_scale_freq_tick topology_scale_freq_tick topology_scale_freq_tick() sfd->set_freq_scale() amu_scale_freq_tick() ... scale *= this_cpu_read(arch_max_freq_scale) ^^^^^^^^^^^^^^^^^^^ ... this_cpu_write(arch_freq_scale, (unsigned long)scale); #define arch_scale_freq_capacity topology_get_freq_scale topology_get_freq_scale(cpu) return per_cpu(arch_freq_scale, cpu) [...]
On Thu, 26 Oct 2023 at 13:19, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: > > On 24/10/2023 11:58, Vincent Guittot wrote: > > On Mon, 23 Oct 2023 at 22:58, Ionela Voinescu <ionela.voinescu@arm.com> wrote: > >> > >> Hi, > >> > >> On Wednesday 18 Oct 2023 at 18:25:40 (+0200), Vincent Guittot wrote: > >>> Use the new capacity_ref_freq to set the ratio that is used by AMU for > >>> computing the arch_scale_freq_capacity(). > >>> This helps to keep everything aligned using the same reference for > >>> computing CPUs capacity. > >>> > >>> The default value of the ratio ensures that arch_scale_freq_capacity() > >>> returns max capacity until it is set to its correct value with the > >>> cpu capacity and capacity_ref_freq. > > Nitpick: Could you mention that arch_max_freq_scale is the default value > for this ratio? Took me a while to recreate the (not so simple) story > for this change, i.e. make the connection between ratio and > arch_max_freq_scale. something like : " The default value of the ratio (saved in per_cpu(arch_max_freq_scale) ensures that arch_scale_freq_capacity() returns max capacity until it is set to its correct value with the cpu capacity and capacity_ref_freq. " Or I can rename the variable per_cpu(arch_max_freq_ratio) > > init_cpu_capacity_callback() > > freq_inv_set_max_ratio() > > u64 ratio > ... > per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio > ^^^^^^^^^^^^^^^^^^^ > > > static struct scale_freq_data amu_sfd = { > .set_freq_scale = amu_scale_freq_tick, > } > > #define arch_scale_freq_tick topology_scale_freq_tick > > topology_scale_freq_tick() > > sfd->set_freq_scale() > > > amu_scale_freq_tick() > > ... > scale *= this_cpu_read(arch_max_freq_scale) > ^^^^^^^^^^^^^^^^^^^ > ... > this_cpu_write(arch_freq_scale, (unsigned long)scale); > > > #define arch_scale_freq_capacity topology_get_freq_scale > > topology_get_freq_scale(cpu) > > return per_cpu(arch_freq_scale, cpu) > > [...] >
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 817d788cd866..0f8f6e90c46d 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -82,7 +82,12 @@ int __init parse_acpi_topology(void) #undef pr_fmt #define pr_fmt(fmt) "AMU: " fmt -static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale); +/* + * Ensure that amu_scale_freq_tick() will return SCHED_CAPACITY_SHIFT until + * the CPU capacity and its assosciated frequency have been correctly + * initialized. + */ +static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale) = (2 * SCHED_CAPACITY_SHIFT); static DEFINE_PER_CPU(u64, arch_const_cycles_prev); static DEFINE_PER_CPU(u64, arch_core_cycles_prev); static cpumask_var_t amu_fie_cpus; @@ -112,9 +117,9 @@ static inline bool freq_counters_valid(int cpu) return true; } -static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) +int freq_inv_set_max_ratio(int cpu, u64 max_rate) { - u64 ratio; + u64 ratio, ref_rate = arch_timer_get_rate(); if (unlikely(!max_rate || !ref_rate)) { pr_debug("CPU%d: invalid maximum or reference frequency.\n", @@ -142,7 +147,7 @@ static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) return -EINVAL; } - per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio; + WRITE_ONCE(per_cpu(arch_max_freq_scale, cpu), (unsigned long)ratio); return 0; } @@ -195,10 +200,7 @@ static void amu_fie_setup(const struct cpumask *cpus) return; for_each_cpu(cpu, cpus) { - if (!freq_counters_valid(cpu) || - freq_inv_set_max_ratio(cpu, - cpufreq_get_hw_max_freq(cpu) * 1000ULL, - arch_timer_get_rate())) + if (!freq_counters_valid(cpu)) return; } diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 2372ce791bb4..3a604b77b12d 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -344,6 +344,11 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) return !ret; } +int __weak freq_inv_set_max_ratio(int cpu, u64 max_rate) +{ + return 0; +} + #ifdef CONFIG_ACPI_CPPC_LIB #include <acpi/cppc_acpi.h> @@ -369,7 +374,6 @@ void topology_init_cpu_capacity_cppc(void) capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]); per_cpu(capacity_ref_freq, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]); - pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n", cpu, raw_capacity[cpu]); continue; @@ -381,6 +385,9 @@ void topology_init_cpu_capacity_cppc(void) } for_each_possible_cpu(cpu) { + freq_inv_set_max_ratio(cpu, + per_cpu(capacity_ref_freq, cpu)); + capacity = raw_capacity[cpu]; capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, capacity_scale); @@ -422,8 +429,11 @@ init_cpu_capacity_callback(struct notifier_block *nb, cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus); - for_each_cpu(cpu, policy->related_cpus) + for_each_cpu(cpu, policy->related_cpus) { per_cpu(capacity_ref_freq, cpu) = policy->cpuinfo.max_freq; + freq_inv_set_max_ratio(cpu, + per_cpu(capacity_ref_freq, cpu)); + } if (cpumask_empty(cpus_to_visit)) { topology_normalize_cpu_scale(); diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index 38ca6c76af56..b6e95d763279 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -99,6 +99,7 @@ void update_siblings_masks(unsigned int cpu); void remove_cpu_topology(unsigned int cpuid); void reset_cpu_topology(void); int parse_acpi_topology(void); +int freq_inv_set_max_ratio(int cpu, u64 max_rate); #endif #endif /* _LINUX_ARCH_TOPOLOGY_H_ */
Use the new capacity_ref_freq to set the ratio that is used by AMU for computing the arch_scale_freq_capacity(). This helps to keep everything aligned using the same reference for computing CPUs capacity. The default value of the ratio ensures that arch_scale_freq_capacity() returns max capacity until it is set to its correct value with the cpu capacity and capacity_ref_freq. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> --- arch/arm64/kernel/topology.c | 18 ++++++++++-------- drivers/base/arch_topology.c | 14 ++++++++++++-- include/linux/arch_topology.h | 1 + 3 files changed, 23 insertions(+), 10 deletions(-)