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Commit 53d56d41 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Joel Fernandes
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BACKPORT: cpufreq: schedutil: Use policy-dependent transition delays 



Make the schedutil governor take the initial (default) value of the
rate_limit_us sysfs attribute from the (new) transition_delay_us
policy parameter (to be set by the scaling driver).

That will allow scaling drivers to make schedutil use smaller default
values of rate_limit_us and reduce the default average time interval
between consecutive frequency changes.

Make intel_pstate set transition_delay_us to 500.

BACKPORT: Modified to support the separate up_rate_limit_us and
down_rate_limit_us (upstream just has a single rate_limit_us). Also
dropped the changes for intel_pstate as there's a merge conflict.

Change-Id: I62a8543879a4d8582cdcb31ebd55607705d1c8b1
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
(cherry picked from commit 1b72e7fd304639f1cd49d1e11955c4974936d88c)
Signed-off-by: default avatarBrendan Jackman <brendan.jackman@arm.com>
parent 36733457

include/linux/cpufreq.h

+8 −0
Original line number Diff line number Diff line
@@ -120,6 +120,14 @@ struct cpufreq_policy { 
	bool			fast_switch_possible;

	bool			fast_switch_enabled;



	/*

	 * Preferred average time interval between consecutive invocations of

	 * the driver to set the frequency for this policy.  To be set by the

	 * scaling driver (0, which is the default, means no preference).

	 */

	unsigned int		up_transition_delay_us;

	unsigned int		down_transition_delay_us;



	 /* Cached frequency lookup from cpufreq_driver_resolve_freq. */

	unsigned int cached_target_freq;

	int cached_resolved_idx;

kernel/sched/cpufreq_schedutil.c

+13 −7
Original line number Diff line number Diff line
@@ -587,7 +587,6 @@ static int sugov_init(struct cpufreq_policy *policy) 
{

	struct sugov_policy *sg_policy;

	struct sugov_tunables *tunables;

	unsigned int lat;

	int ret = 0;



	/* State should be equivalent to EXIT */
@@ -626,6 +625,12 @@ static int sugov_init(struct cpufreq_policy *policy) 
		goto stop_kthread;

	}



	if (policy->up_transition_delay_us && policy->down_transition_delay_us) {

		tunables->up_rate_limit_us = policy->up_transition_delay_us;

		tunables->down_rate_limit_us = policy->down_transition_delay_us;

	} else {

		unsigned int lat;



                tunables->up_rate_limit_us = LATENCY_MULTIPLIER;

                tunables->down_rate_limit_us = LATENCY_MULTIPLIER;

		lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
@@ -633,6 +638,7 @@ static int sugov_init(struct cpufreq_policy *policy) 
                        tunables->up_rate_limit_us *= lat;

                        tunables->down_rate_limit_us *= lat;

                }

	}



	policy->governor_data = sg_policy;

	sg_policy->tunables = tunables;