From c79268e1feec03b213e1862764d5769f68136d42 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 21 Feb 2017 10:15:18 +0530 Subject: [PATCH] FROM-LIST: cpufreq: schedutil: Redefine the rate_limit_us tunable The rate_limit_us tunable is intended to reduce the possible overhead from running the schedutil governor. However, that overhead can be divided into two separate parts: the governor computations and the invocation of the scaling driver to set the CPU frequency. The latter is where the real overhead comes from. The former is much less expensive in terms of execution time and running it every time the governor callback is invoked by the scheduler, after rate_limit_us interval has passed since the last frequency update, would not be a problem. For this reason, redefine the rate_limit_us tunable so that it means the minimum time that has to pass between two consecutive invocations of the scaling driver by the schedutil governor (to set the CPU frequency). Change-Id: Iced64116b826c25441ef537c27a3dabfcf81919e Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki [pulled from linux-pm linux-next https://patchwork.kernel.org/patch/9583949/ ] Signed-off-by: Chris Redpath --- kernel/sched/cpufreq_schedutil.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 5c7c52077ad1..191ba36a9eeb 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -129,14 +129,13 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, if (sugov_up_down_rate_limit(sg_policy, time, next_freq)) return; - sg_policy->last_freq_update_time = time; - if (policy->fast_switch_enabled) { if (sg_policy->next_freq == next_freq) { trace_cpu_frequency(policy->cur, smp_processor_id()); return; } sg_policy->next_freq = next_freq; + sg_policy->last_freq_update_time = time; next_freq = cpufreq_driver_fast_switch(policy, next_freq); if (next_freq == CPUFREQ_ENTRY_INVALID) return; @@ -145,6 +144,7 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, trace_cpu_frequency(next_freq, smp_processor_id()); } else if (sg_policy->next_freq != next_freq) { sg_policy->next_freq = next_freq; + sg_policy->last_freq_update_time = time; sg_policy->work_in_progress = true; irq_work_queue(&sg_policy->irq_work); } -- 2.34.1