[PATCH v6 6/7] cpufreq: Skip inefficient frequencies
From: Vincent Donnefort <hidden>
Date: 2021-08-31 10:24:45
Subsystem:
cpu frequency scaling framework, the rest · Maintainers:
"Rafael J. Wysocki", Viresh Kumar, Linus Torvalds
CPUFreq governors that do DVFS (i.e. CPUFREQ_GOV_DYNAMIC_SWITCHING flag) can skip frequencies marked as inefficient, as long as the efficient frequency found meet the policy maximum requirement. Signed-off-by: Vincent Donnefort <redacted>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7d5f170ecad1..b46fe2d7baf1 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c@@ -2295,6 +2295,44 @@ __weak struct cpufreq_governor *cpufreq_fallback_governor(void) return NULL; } +static inline bool +cpufreq_can_skip_inefficiencies(struct cpufreq_policy *policy) +{ + struct cpufreq_frequency_table *pos; + bool valid = false; + int idx; + + if (!(policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) + return false; + + if (policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED) + return false; + + /* Is there at least one inefficiency ? */ + cpufreq_for_each_valid_entry(pos, policy->freq_table) { + if (pos->flags & CPUFREQ_INEFFICIENT_FREQ) { + valid = true; + break; + } + } + + if (!valid) + return false; + + /* + * Has cpufreq_table_update_efficiencies been called? i.e. is the + * highest frequency efficient. + */ + cpufreq_for_each_valid_entry_idx(pos, policy->freq_table, idx) { + valid = !!(idx == pos->efficient); + if (policy->freq_table_sorted == + CPUFREQ_TABLE_SORTED_DESCENDING) + break; + } + + return valid; +} + static int cpufreq_init_governor(struct cpufreq_policy *policy) { int ret;
@@ -2337,6 +2375,7 @@ static int cpufreq_init_governor(struct cpufreq_policy *policy) } policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET); + policy->skip_inefficiencies = cpufreq_can_skip_inefficiencies(policy); return 0; }
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 4e901ebd104d..cb09afbf01e2 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h@@ -117,6 +117,13 @@ struct cpufreq_policy { bool strict_target; /* + * Set if the CPUFREQ_GOV_DYNAMIC_SWITCHING flag is set for the current + * governor and if inefficient frequencies were found in the frequency + * table. + */ + bool skip_inefficiencies; + + /* * Preferred average time interval between consecutive invocations of * the driver to set the frequency for this policy. To be set by the * scaling driver (0, which is the default, means no preference).
@@ -972,25 +979,46 @@ static inline int cpufreq_table_find_index_c(struct cpufreq_policy *policy, return cpufreq_table_find_index_dc(policy, target_freq); } +static inline unsigned int +cpufreq_frequency_find_efficient(struct cpufreq_policy *policy, + unsigned int idx) +{ + struct cpufreq_frequency_table *table = policy->freq_table; + unsigned int efficient_idx = table[idx].efficient; + + return table[efficient_idx].frequency <= policy->max ? efficient_idx : + idx; +} + static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { + int idx; + if (unlikely(policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED)) return cpufreq_table_index_unsorted(policy, target_freq, relation); switch (relation) { case CPUFREQ_RELATION_L: - return cpufreq_table_find_index_l(policy, target_freq); + idx = cpufreq_table_find_index_l(policy, target_freq); + break; case CPUFREQ_RELATION_H: - return cpufreq_table_find_index_h(policy, target_freq); + idx = cpufreq_table_find_index_h(policy, target_freq); + break; case CPUFREQ_RELATION_C: - return cpufreq_table_find_index_c(policy, target_freq); + idx = cpufreq_table_find_index_c(policy, target_freq); + break; default: WARN_ON_ONCE(1); return 0; } + + if (policy->skip_inefficiencies) + idx = cpufreq_frequency_find_efficient(policy, idx); + + return idx; } static inline int cpufreq_table_count_valid_entries(const struct cpufreq_policy *policy)
--
2.7.4