On Wed, Oct 18, 2023 at 6:25 PM Vincent Guittot
<vincent.guittot@xxxxxxxxxx> wrote:
>
> cpuinfo.max_freq can change at runtime because of boost as an example. This
> implies that the value could be different from the frequency that has been
> used to compute the capacity of a CPU.
>
> The new arch_scale_freq_ref() returns a fixed and coherent frequency
> that can be used to compute the capacity for a given frequency.
>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx>
> Tested-by: Lukasz Luba <lukasz.luba@xxxxxxx>
Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> ---
> drivers/cpufreq/cpufreq.c | 4 ++--
> include/linux/cpufreq.h | 9 +++++++++
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 60ed89000e82..8c4f9c2f9c44 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -454,7 +454,7 @@ void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
>
> arch_set_freq_scale(policy->related_cpus,
> policy->cur,
> - policy->cpuinfo.max_freq);
> + arch_scale_freq_ref(policy->cpu));
>
> spin_lock(&policy->transition_lock);
> policy->transition_ongoing = false;
> @@ -2174,7 +2174,7 @@ unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
>
> policy->cur = freq;
> arch_set_freq_scale(policy->related_cpus, freq,
> - policy->cpuinfo.max_freq);
> + arch_scale_freq_ref(policy->cpu));
> cpufreq_stats_record_transition(policy, freq);
>
> if (trace_cpu_frequency_enabled()) {
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 71d186d6933a..bbc483b4b6e5 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -1211,6 +1211,15 @@ void arch_set_freq_scale(const struct cpumask *cpus,
> {
> }
> #endif
> +
> +#ifndef arch_scale_freq_ref
> +static __always_inline
> +unsigned int arch_scale_freq_ref(int cpu)
> +{
> + return 0;
> +}
> +#endif
> +
> /* the following are really really optional */
> extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
> extern struct freq_attr cpufreq_freq_attr_scaling_boost_freqs;
> --
> 2.34.1
>
