Messages in this thread Patch in this message | | | Date | Wed, 14 May 2014 21:05:52 +0300 | From | Stratos Karafotis <> | Subject | [PATCH RESEND] cpufreq: Break out early when frequency equals target_freq |
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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> --- drivers/cpufreq/freq_table.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index 8e518c6..1632981 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; -- 1.9.0
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