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From fd991617b51a628a72bdb45b20fbc5c01d666b70 Mon Sep 17 00:00:00 2001
From: Gaku Inami <gaku.inami.xw@bp.renesas.com>
Date: Fri, 7 Jul 2017 15:04:31 +0900
Subject: [PATCH 92/92] cpufreq: schedutil: Use policy-dependent transition
delays for R-Car
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.
The cpufreq-dt driver for R-Car H3/M3 set transition_delay_us to value
same as transition_latency.
Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
---
drivers/cpufreq/cpufreq-dt.c | 4 ++++
include/linux/cpufreq.h | 7 +++++++
kernel/sched/cpufreq_schedutil.c | 15 ++++++++++-----
3 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index 5c07ae0..57cd54e 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -276,6 +276,10 @@ static int cpufreq_init(struct cpufreq_policy *policy)
policy->cpuinfo.transition_latency = transition_latency;
+#if IS_ENABLED(CONFIG_ARCH_R8A7795) || IS_ENABLED(CONFIG_ARCH_R8A7796)
+ policy->transition_delay_us = transition_latency;
+#endif
+
return 0;
out_free_cpufreq_table:
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 32dc0cbd..7df5d88 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -120,6 +120,13 @@ 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 transition_delay_us;
+
/* Cached frequency lookup from cpufreq_driver_resolve_freq. */
unsigned int cached_target_freq;
int cached_resolved_idx;
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 42a220e..9668e0e 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -473,7 +473,6 @@ 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 */
@@ -512,10 +511,16 @@ static int sugov_init(struct cpufreq_policy *policy)
goto stop_kthread;
}
- tunables->rate_limit_us = LATENCY_MULTIPLIER;
- lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
- if (lat)
- tunables->rate_limit_us *= lat;
+ 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;
+ }
policy->governor_data = sg_policy;
sg_policy->tunables = tunables;
--
1.9.1
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