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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-03-22 18:32:47 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-03-24 02:57:22 +0100
commit38d4ea229d25d30be6bf41bcd6cd663a587866ca (patch)
treee42f08d1d926e1e41df166d863d132d75be24c5b /kernel/sched
parentb7eaf1aab9f8bd2e49fceed77ebc66c1b5800718 (diff)
downloadlinux-38d4ea229d25d30be6bf41bcd6cd663a587866ca.tar.bz2
cpufreq: schedutil: Trace frequency only if it has changed
sugov_update_commit() calls trace_cpu_frequency() to record the current CPU frequency if it has not changed in the fast switch case to prevent utilities from getting confused (they may report that the CPU is idle if the frequency has not been recorded for too long, for example). However, that may cause the tracepoint to be triggered quite often for no real reason (if the frequency doesn't change, we will not modify the last update time stamp and governor computations may run again shortly when that happens), so don't do that (arguably, it is done to work around a utilities bug anyway). That allows code duplication in sugov_update_commit() to be reduced somewhat too. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/cpufreq_schedutil.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index c1ffb5dc8af6..1054f868d95c 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -98,22 +98,20 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
{
struct cpufreq_policy *policy = sg_policy->policy;
+ if (sg_policy->next_freq == next_freq)
+ return;
+
+ sg_policy->next_freq = next_freq;
+ 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;
policy->cur = next_freq;
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;
+ } else {
sg_policy->work_in_progress = true;
irq_work_queue(&sg_policy->irq_work);
}