| Message ID | 46734e7c365a024632e8b1d52990d4400899727b.1500373914.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Wed, Jul 19, 2017 at 03:42:42PM +0530, Viresh Kumar wrote: > The policy->transition_delay_us field is used only by the schedutil > governor currently, and this field describes how fast the driver wants > the cpufreq governor to change CPUs frequency. It should rather be a > common thing across all governors, as it doesn't have any schedutil > dependency here. > > Create a new helper cpufreq_policy_transition_delay_us() to get the > transition delay across all governors. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/cpufreq.c | 15 +++++++++++++++ > drivers/cpufreq/cpufreq_governor.c | 9 +-------- > include/linux/cpufreq.h | 1 + > kernel/sched/cpufreq_schedutil.c | 11 +---------- > 4 files changed, 18 insertions(+), 18 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 9bf97a366029..c426d21822f7 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -524,6 +524,21 @@ unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, > } > EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq); > > +unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy) > +{ > + unsigned int latency; > + > + if (policy->transition_delay_us) > + return policy->transition_delay_us; > + > + latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC; > + if (latency) > + return latency * LATENCY_MULTIPLIER; > + > + return LATENCY_MULTIPLIER; > +} > +EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us); I realize you're just moving code about, but _why_ are we doing that division?
On 24-07-17, 18:17, Peter Zijlstra wrote: > On Wed, Jul 19, 2017 at 03:42:42PM +0530, Viresh Kumar wrote: > > The policy->transition_delay_us field is used only by the schedutil > > governor currently, and this field describes how fast the driver wants > > the cpufreq governor to change CPUs frequency. It should rather be a > > common thing across all governors, as it doesn't have any schedutil > > dependency here. > > > > Create a new helper cpufreq_policy_transition_delay_us() to get the > > transition delay across all governors. > > > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > > --- > > drivers/cpufreq/cpufreq.c | 15 +++++++++++++++ > > drivers/cpufreq/cpufreq_governor.c | 9 +-------- > > include/linux/cpufreq.h | 1 + > > kernel/sched/cpufreq_schedutil.c | 11 +---------- > > 4 files changed, 18 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > > index 9bf97a366029..c426d21822f7 100644 > > --- a/drivers/cpufreq/cpufreq.c > > +++ b/drivers/cpufreq/cpufreq.c > > @@ -524,6 +524,21 @@ unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, > > } > > EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq); > > > > +unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy) > > +{ > > + unsigned int latency; > > + > > + if (policy->transition_delay_us) > > + return policy->transition_delay_us; > > + > > + latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC; > > + if (latency) > > + return latency * LATENCY_MULTIPLIER; > > + > > + return LATENCY_MULTIPLIER; > > +} > > +EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us); > > I realize you're just moving code about, but _why_ are we doing that > division? We are doing division by NSEC_PER_USEC because the values of sampling_rate and rate_limit_us are in us, while transition_latency is in ns. We shouldn't be breaking the userspace ABI and so if we want, we can actually make transition_latency be stored in us instead. Though I am not sure why are we multiplying with LATENCY_MULTIPLIER (1000) as that seems to be a huge value.
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9bf97a366029..c426d21822f7 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -524,6 +524,21 @@ unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq); +unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy) +{ + unsigned int latency; + + if (policy->transition_delay_us) + return policy->transition_delay_us; + + latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC; + if (latency) + return latency * LATENCY_MULTIPLIER; + + return LATENCY_MULTIPLIER; +} +EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us); + /********************************************************************* * SYSFS INTERFACE * *********************************************************************/ diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 858081f9c3d7..eed069ecfd5e 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -389,7 +389,6 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy) struct dbs_governor *gov = dbs_governor_of(policy); struct dbs_data *dbs_data; struct policy_dbs_info *policy_dbs; - unsigned int latency; int ret = 0; /* State should be equivalent to EXIT */ @@ -428,13 +427,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy) if (ret) goto free_policy_dbs_info; - /* policy latency is in ns. Convert it to us first */ - latency = policy->cpuinfo.transition_latency / 1000; - if (latency == 0) - latency = 1; - - /* Bring kernel and HW constraints together */ - dbs_data->sampling_rate = LATENCY_MULTIPLIER * latency; + dbs_data->sampling_rate = cpufreq_policy_transition_delay_us(policy); if (!have_governor_per_policy()) gov->gdbs_data = dbs_data; diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 02aec384cab9..aaadfc543f63 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -523,6 +523,7 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int relation); unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, unsigned int target_freq); +unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy); int cpufreq_register_governor(struct cpufreq_governor *governor); void cpufreq_unregister_governor(struct cpufreq_governor *governor); diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 29a397067ffa..89c4dd9777bb 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -528,16 +528,7 @@ static int sugov_init(struct cpufreq_policy *policy) goto stop_kthread; } - if (policy->transition_delay_us) { - tunables->rate_limit_us = policy->transition_delay_us; - } else { - unsigned int lat; - - tunables->rate_limit_us = LATENCY_MULTIPLIER; - lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC; - if (lat) - tunables->rate_limit_us *= lat; - } + tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy); policy->governor_data = sg_policy; sg_policy->tunables = tunables;
The policy->transition_delay_us field is used only by the schedutil governor currently, and this field describes how fast the driver wants the cpufreq governor to change CPUs frequency. It should rather be a common thing across all governors, as it doesn't have any schedutil dependency here. Create a new helper cpufreq_policy_transition_delay_us() to get the transition delay across all governors. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq.c | 15 +++++++++++++++ drivers/cpufreq/cpufreq_governor.c | 9 +-------- include/linux/cpufreq.h | 1 + kernel/sched/cpufreq_schedutil.c | 11 +---------- 4 files changed, 18 insertions(+), 18 deletions(-)