Messages in this thread | | | From | Vincent Guittot <> | Date | Mon, 18 Sep 2023 13:23:59 +0200 | Subject | Re: [PATCH 2/4] topology: add a new arch_scale_freq_reference |
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On Mon, 4 Sept 2023 at 14:34, Lukasz Luba <lukasz.luba@arm.com> wrote: > > Hi Vincent, > > > On 9/1/23 14:03, Vincent Guittot wrote: > > Create a new method to get a unique and fixed max frequency. Currently > > cpuinfo.max_freq or last item of performance domain are used as the max > > frequency when computing the frequency for a level of utilization but: > > - cpuinfo_max_freq can change at runtime. boost is one example of > > such change. > > - cpuinfo.max_freq and last item of the PD can be different leading to > > different results betwen cpufreq and energy model. > > > > We need to save the max frequency that has been used when computing the > > CPUs capacity and use this fixed and coherent value to convert between > > frequency and CPU's capacity. > > > > In fact, we already save the frequency that has been used when computing > > the capacity of each CPU. We extend the precision to save khZ instead of > > Mhz currently and we modify the type to be aligned with other variables > > used when converting frequency to capacity and the other way. > > I do like this 'kHz' change. We also use kHz in the EM, so better > aligned now. > > > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > > --- > > arch/arm/include/asm/topology.h | 1 + > > arch/arm64/include/asm/topology.h | 1 + > > arch/riscv/include/asm/topology.h | 1 + > > drivers/base/arch_topology.c | 9 +++------ > > include/linux/arch_topology.h | 7 +++++++ > > 5 files changed, 13 insertions(+), 6 deletions(-) > > > > diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h > > index c7d2510e5a78..853c4f81ba4a 100644 > > --- a/arch/arm/include/asm/topology.h > > +++ b/arch/arm/include/asm/topology.h > > @@ -13,6 +13,7 @@ > > #define arch_set_freq_scale topology_set_freq_scale > > #define arch_scale_freq_capacity topology_get_freq_scale > > #define arch_scale_freq_invariant topology_scale_freq_invariant > > +#define arch_scale_freq_ref topology_get_freq_ref > > #endif > > > > /* Replace task scheduler's default cpu-invariant accounting */ > > diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h > > index 9fab663dd2de..a323b109b9c4 100644 > > --- a/arch/arm64/include/asm/topology.h > > +++ b/arch/arm64/include/asm/topology.h > > @@ -23,6 +23,7 @@ void update_freq_counters_refs(void); > > #define arch_set_freq_scale topology_set_freq_scale > > #define arch_scale_freq_capacity topology_get_freq_scale > > #define arch_scale_freq_invariant topology_scale_freq_invariant > > +#define arch_scale_freq_ref topology_get_freq_ref > > > > #ifdef CONFIG_ACPI_CPPC_LIB > > #define arch_init_invariance_cppc topology_init_cpu_capacity_cppc > > diff --git a/arch/riscv/include/asm/topology.h b/arch/riscv/include/asm/topology.h > > index e316ab3b77f3..61183688bdd5 100644 > > --- a/arch/riscv/include/asm/topology.h > > +++ b/arch/riscv/include/asm/topology.h > > @@ -9,6 +9,7 @@ > > #define arch_set_freq_scale topology_set_freq_scale > > #define arch_scale_freq_capacity topology_get_freq_scale > > #define arch_scale_freq_invariant topology_scale_freq_invariant > > +#define arch_scale_freq_ref topology_get_freq_ref > > > > /* Replace task scheduler's default cpu-invariant accounting */ > > #define arch_scale_cpu_capacity topology_get_cpu_scale > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > > index b741b5ba82bd..75fa67477a9d 100644 > > --- a/drivers/base/arch_topology.c > > +++ b/drivers/base/arch_topology.c > > @@ -26,7 +26,7 @@ > > static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); > > static struct cpumask scale_freq_counters_mask; > > static bool scale_freq_invariant; > > -static DEFINE_PER_CPU(u32, freq_factor) = 1; > > +DEFINE_PER_CPU(unsigned long, freq_factor) = 1; > > Why it's not static now?
it can be accessed outside with inline function like cpu_scale and arch_freq_scale
> > > > > static bool supports_scale_freq_counters(const struct cpumask *cpus) > > { > > @@ -183,10 +183,7 @@ void topology_update_thermal_pressure(const struct cpumask *cpus, > > > > cpu = cpumask_first(cpus); > > max_capacity = arch_scale_cpu_capacity(cpu); > > - max_freq = per_cpu(freq_factor, cpu); > > - > > - /* Convert to MHz scale which is used in 'freq_factor' */ > > - capped_freq /= 1000; > > + max_freq = arch_scale_freq_ref(cpu); > > > > /* > > * Handle properly the boost frequencies, which should simply clean > > @@ -411,7 +408,7 @@ 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) > > - per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq / 1000; > > + per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq; > > > > 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 a07b510e7dc5..7a2dba9c3dc0 100644 > > --- a/include/linux/arch_topology.h > > +++ b/include/linux/arch_topology.h > > @@ -27,6 +27,13 @@ static inline unsigned long topology_get_cpu_scale(int cpu) > > > > void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity); > > > > +DECLARE_PER_CPU(unsigned long, freq_factor); > > + > > +static inline unsigned long topology_get_freq_ref(int cpu) > > +{ > > + return per_cpu(freq_factor, cpu); > > +} > > + > > DECLARE_PER_CPU(unsigned long, arch_freq_scale); > > > > static inline unsigned long topology_get_freq_scale(int cpu) > > Apart from that 'static' missing, that looks good. > > Regards, > Lukasz
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