cpufreq: Break out early when frequency equals target_freq

Many drivers keep frequencies in frequency table in ascending
or descending order. When governor tries to change to policy->min
or policy->max respectively then the cpufreq_frequency_table_target
could return on first iteration. This will save some iteration cycles.

So, break out early when a frequency in cpufreq_frequency_table
equals to target one.

Testing this during kernel compilation using ondemand governor
with a frequency table in ascending order, the
cpufreq_frequency_table_target returned early on the first
iteration at about 30% of times called.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 8e518c689393..1632981c4b25 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -137,9 +137,13 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
                 i = pos - table;
                 if ((freq < policy->min) || (freq > policy->max))
                         continue;
+                if (freq == target_freq) {
+                        optimal.driver_data = i;
+                        break;
+                }
                 switch (relation) {
                 case CPUFREQ_RELATION_H:
-                        if (freq <= target_freq) {
+                        if (freq < target_freq) {
                                 if (freq >= optimal.frequency) {
                                         optimal.frequency = freq;
                                         optimal.driver_data = i;
@@ -152,7 +156,7 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
                         }
                         break;
                 case CPUFREQ_RELATION_L:
-                        if (freq >= target_freq) {
+                        if (freq > target_freq) {
                                 if (freq <= optimal.frequency) {
                                         optimal.frequency = freq;
                                         optimal.driver_data = i;