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cpufreq: ondemand: update update_sampling_rate() to make it more efficient

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Currently update_sampling_rate() runs over each online CPU and
cancels/queues timers on all policy->cpus every time. This should be
done just once for any cpu belonging to a policy.

Create a cpumask and keep on clearing it as and when we process
policies, so that we don't have to traverse through all CPUs of the same
policy.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2015-12-03 09:37:54 +05:30 committed by Rafael J. Wysocki
parent 70f43e5e79
commit f08f638b9c
1 changed files with 11 additions and 1 deletions
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12
drivers/cpufreq/cpufreq_ondemand.c
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@ -246,6 +246,7 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
unsigned int new_rate)
{
struct od_dbs_tuners *od_tuners = dbs_data->tuners;
struct cpumask cpumask;
int cpu;
od_tuners->sampling_rate = new_rate = max(new_rate,
@ -256,7 +257,9 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
*/
mutex_lock(&od_dbs_cdata.mutex);
for_each_online_cpu(cpu) {
cpumask_copy(&cpumask, cpu_online_mask);
for_each_cpu(cpu, &cpumask) {
struct cpufreq_policy *policy;
struct od_cpu_dbs_info_s *dbs_info;
struct cpu_dbs_info *cdbs;
@ -276,6 +279,9 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
policy = shared->policy;
/* clear all CPUs of this policy */
cpumask_andnot(&cpumask, &cpumask, policy->cpus);
/*
* Update sampling rate for CPUs whose policy is governed by
* dbs_data. In case of governor_per_policy, only a single
@ -285,6 +291,10 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
if (dbs_data != policy->governor_data)
continue;
/*
* Checking this for any CPU should be fine, timers for all of
* them are scheduled together.
*/
next_sampling = jiffies + usecs_to_jiffies(new_rate);
appointed_at = dbs_info->cdbs.timer.expires;