On Monday, July 27, 2015 05:58:11 PM Viresh Kumar wrote:
Currently update_sampling_rate() runs over each online CPU and cancels/queues work on it. Its very inefficient for the case where a single policy manages multiple CPUs, as they can be processed together.
Also drop the unnecessary cancel_delayed_work_sync() as we are doing a mod_delayed_work_on() in gov_queue_work(), which will take care of pending works for us.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
drivers/cpufreq/cpufreq_ondemand.c | 31 ++++++++++++++++++------------- 1 file changed, 18 insertions(+), 13 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index f1551fc7b4fd..a6f579e40ce2 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -247,40 +247,45 @@ static void update_sampling_rate(struct dbs_data *dbs_data, unsigned int new_rate) { struct od_dbs_tuners *od_tuners = dbs_data->tuners;
- struct cpufreq_policy *policy;
- struct od_cpu_dbs_info_s *dbs_info;
- unsigned long next_sampling, appointed_at;
- struct cpumask cpumask; int cpu;
- cpumask_copy(&cpumask, cpu_online_mask);
- od_tuners->sampling_rate = new_rate = max(new_rate, dbs_data->min_sampling_rate);
- for_each_online_cpu(cpu) {
struct cpufreq_policy *policy;
struct od_cpu_dbs_info_s *dbs_info;
unsigned long next_sampling, appointed_at;
- for_each_cpu(cpu, &cpumask) { policy = cpufreq_cpu_get(cpu); if (!policy) continue;
/* clear all CPUs of this policy */
cpumask_andnot(&cpumask, &cpumask, policy->cpus);
Well, this is not exactly straightforward, but should work.
- if (policy->governor != &cpufreq_gov_ondemand) { cpufreq_cpu_put(policy); continue; }
- dbs_info = &per_cpu(od_cpu_dbs_info, cpu); cpufreq_cpu_put(policy);
if (!delayed_work_pending(&dbs_info->cdbs.dwork))
/* Make sure the work is not canceled on policy->cpus */
I'm not sure what scenario can lead to that. Care to explain?
if (!dbs_info->cdbs.shared->policy) continue;
next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->cdbs.dwork.timer.expires;
For that to work we always need to do stuff for policy->cpus in sync. Do we?
if (time_before(next_sampling, appointed_at)) {
cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
gov_queue_work(dbs_data, policy,
usecs_to_jiffies(new_rate),
cpumask_of(cpu));
if (!time_before(next_sampling, appointed_at))
continue;
}
gov_queue_work(dbs_data, policy, usecs_to_jiffies(new_rate),
}policy->cpus);
}
Thanks, Rafael