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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-03-29 20:19:03 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-04-07 19:26:44 +0200
commitd3c33be1f350e7fd2b04381b000f3f950bd1ba77 (patch)
treea89c96fbacaef035bb19cb2f19c48d3328d9162a /drivers/cpuidle
parent2ab80d46fead0309d7f190d8023c8d64b2ffcbd5 (diff)
downloadlinux-d3c33be1f350e7fd2b04381b000f3f950bd1ba77.tar.bz2
cpuidle: teo: Adjust handling of very short idle times
If the time till the next timer event is shorter than the target residency of the first idle state (state 0), the TEO governor does not update its metrics for any idle states, but arguably it should record a "hit" for idle state 0 in that case, so modify it to do that. Accordingly, also make it record an "early hit" for idle state 0 if the measured idle duration is less than its target residency, which allows one branch more to be dropped from teo_update(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/governors/teo.c32
1 files changed, 15 insertions, 17 deletions
diff --git a/drivers/cpuidle/governors/teo.c b/drivers/cpuidle/governors/teo.c
index 6deaaf5f05b5..7dcfc9499910 100644
--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -117,7 +117,8 @@ static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
- int i, idx_hit = -1, idx_timer = -1;
+ int i, idx_hit = 0, idx_timer = 0;
+ unsigned int hits, misses;
u64 measured_ns;
if (cpu_data->time_span_ns >= cpu_data->sleep_length_ns) {
@@ -174,25 +175,22 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* also increase the "early hits" metric for the state that actually
* matches the measured idle duration.
*/
- if (idx_timer >= 0) {
- unsigned int hits = cpu_data->states[idx_timer].hits;
- unsigned int misses = cpu_data->states[idx_timer].misses;
-
- hits -= hits >> DECAY_SHIFT;
- misses -= misses >> DECAY_SHIFT;
-
- if (idx_timer > idx_hit) {
- misses += PULSE;
- if (idx_hit >= 0)
- cpu_data->states[idx_hit].early_hits += PULSE;
- } else {
- hits += PULSE;
- }
+ hits = cpu_data->states[idx_timer].hits;
+ hits -= hits >> DECAY_SHIFT;
+
+ misses = cpu_data->states[idx_timer].misses;
+ misses -= misses >> DECAY_SHIFT;
- cpu_data->states[idx_timer].misses = misses;
- cpu_data->states[idx_timer].hits = hits;
+ if (idx_timer == idx_hit) {
+ hits += PULSE;
+ } else {
+ misses += PULSE;
+ cpu_data->states[idx_hit].early_hits += PULSE;
}
+ cpu_data->states[idx_timer].misses = misses;
+ cpu_data->states[idx_timer].hits = hits;
+
/*
* Save idle duration values corresponding to non-timer wakeups for
* pattern detection.