| Message ID | d2760eca0b3fd5e427d004120bdb82c1aed215ca.1437999691.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08-09-15, 03:33, Rafael J. Wysocki wrote: > > + /* Make sure the work is not canceled on policy->cpus */ > > I'm not sure what scenario can lead to that. Care to explain? CPUFREQ_GOV_STOP event called for the policy and so all its works are in canceled state. > > + 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? Hmm, we are not in 100% sync for sure. Will check that again.
On 08-09-15, 07:41, Viresh Kumar wrote: > > > 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? > > Hmm, we are not in 100% sync for sure. Will check that again. On the other hand, if we decide to apply 7/9 as well, then this is anyway going to get removed :)
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); + 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 */ + if (!dbs_info->cdbs.shared->policy) continue; next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->cdbs.dwork.timer.expires; - 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); } }
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(-)