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[RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well

Started byViresh Kumar <viresh.kumar@linaro.org>
First post2017-07-13 07:50 +0200
Last post2017-07-13 18:40 +0200
Articles 2 — 2 participants

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  [RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-13 07:50 +0200
    Re: [RFC V2 4/6] cpufreq: Use transition_delay_us for legacy  governors as well "Rafael J. Wysocki" <rafael@kernel.org> - 2017-07-13 18:40 +0200

#1686256 — [RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well

FromViresh Kumar <viresh.kumar@linaro.org>
Date2017-07-13 07:50 +0200
Subject[RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well
Message-ID<u2FaF-1xh-7@gated-at.bofh.it>
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_governor.c |  9 +--------
 include/linux/cpufreq.h            | 15 +++++++++++++++
 kernel/sched/cpufreq_schedutil.c   | 11 +----------
 3 files changed, 17 insertions(+), 18 deletions(-)

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 00e4c40a3249..14f0ab61ed17 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -532,6 +532,21 @@ static inline void cpufreq_policy_apply_limits(struct cpufreq_policy *policy)
 		__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
 }
 
+static inline unsigned int
+cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
+{
+	unsigned int delay_us = LATENCY_MULTIPLIER, latency;
+
+	if (policy->transition_delay_us)
+		return policy->transition_delay_us;
+
+	latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
+	if (latency)
+		delay_us *= latency;
+
+	return delay_us;
+}
+
 /* Governor attribute set */
 struct gov_attr_set {
 	struct kobject kobj;
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index ab9d7a1b43dc..5c72c569ec2f 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;
-- 
2.13.0.71.gd7076ec9c9cb

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#1686775 — Re: [RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well

From"Rafael J. Wysocki" <rafael@kernel.org>
Date2017-07-13 18:40 +0200
SubjectRe: [RFC V2 4/6] cpufreq: Use transition_delay_us for legacy governors as well
Message-ID<u2PjI-7XN-17@gated-at.bofh.it>
In reply to#1686256
On Thu, Jul 13, 2017 at 7:40 AM, Viresh Kumar <viresh.kumar@linaro.org> 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_governor.c |  9 +--------
>  include/linux/cpufreq.h            | 15 +++++++++++++++
>  kernel/sched/cpufreq_schedutil.c   | 11 +----------
>  3 files changed, 17 insertions(+), 18 deletions(-)
>
> 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 00e4c40a3249..14f0ab61ed17 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -532,6 +532,21 @@ static inline void cpufreq_policy_apply_limits(struct cpufreq_policy *policy)
>                 __cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
>  }
>
> +static inline unsigned int
> +cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
> +{
> +       unsigned int delay_us = LATENCY_MULTIPLIER, latency;
> +
> +       if (policy->transition_delay_us)
> +               return policy->transition_delay_us;
> +
> +       latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
> +       if (latency)
> +               delay_us *= latency;
> +
> +       return delay_us;
> +}

Not in the header, please, and I don't think you need delay_us:

    latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
    if (latency)
        return latency * LATENCY_MULTIPLIER;

    return LATENCY_MULTIPLIER;

Thanks,
Rafael

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