Re: [PATCH v3 5/6] cpufreq: Mark inefficient frequencies using the Energy Model

[Matthias Kaehlcke <mka@chromium.org>]

On Fri, Jun 04, 2021 at 12:06:00PM +0100, Vincent Donnefort wrote:
> The Energy Model has a 1:1 mapping between OPPs and performance states
> (em_perf_state). We can then read which states are inefficient and use this
> information to mark the cpufreq table.
> 
> Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 7431f40a..34d344d 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -19,6 +19,7 @@
>  #include <linux/cpu_cooling.h>
>  #include <linux/delay.h>
>  #include <linux/device.h>
> +#include <linux/energy_model.h>
>  #include <linux/init.h>
>  #include <linux/kernel_stat.h>
>  #include <linux/module.h>
> @@ -1317,6 +1318,31 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
>  	kfree(policy);
>  }
>  
> +static void cpufreq_inefficiencies_from_em(struct cpufreq_policy *policy,
> +					   struct em_perf_domain *em_pd)
> +{
> +	struct cpufreq_frequency_table *pos, *table = policy->freq_table;
> +	struct em_perf_state *em_table;
> +	int i;
> +
> +	if (!em_pd)
> +		return;
> +
> +	em_table = em_pd->table;
> +
> +	for (i = 0; i < em_pd->nr_perf_states; i++) {
> +		if (!(em_table[i].flags & EM_PERF_STATE_INEFFICIENT))
> +			continue;
> +
> +		cpufreq_for_each_valid_entry(pos, table) {
> +			if (pos->frequency == em_table[i].frequency) {
> +				pos->flags |= CPUFREQ_INEFFICIENT_FREQ;
> +				break;
> +			}
> +		}
> +	}
> +}
> +
>  static int cpufreq_online(unsigned int cpu)
>  {
>  	struct cpufreq_policy *policy;
> @@ -1371,6 +1397,12 @@ static int cpufreq_online(unsigned int cpu)
>  			goto out_free_policy;
>  		}
>  
> +		/*
> +		 * Sync potential inefficiencies with an Energy Model that the
> +		 * driver might have registered.
> +		 */
> +		cpufreq_inefficiencies_from_em(policy, em_cpu_get(cpu));
> +
>  		ret = cpufreq_table_validate_and_sort(policy);
>  		if (ret)
>  			goto out_exit_policy;

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>