cpuidle: Add decaying history logic to menu idle predictor

[pandora-kernel.git] / drivers / cpuidle / governors / menu.c

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 8d7cf3f..f1df59f 100644 (file)
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -15,12 +15,14 @@
 #include <linux/tick.h>
 
 #define BREAK_FUZZ     4       /* 4 us */
+#define PRED_HISTORY_PCT       50
 
 struct menu_device {
        int             last_state_idx;
 
        unsigned int    expected_us;
        unsigned int    predicted_us;
+       unsigned int    current_predicted_us;
        unsigned int    last_measured_us;
        unsigned int    elapsed_us;
 };
@@ -47,6 +49,12 @@ static int menu_select(struct cpuidle_device *dev)
        data->expected_us =
                (u32) ktime_to_ns(tick_nohz_get_sleep_length()) / 1000;
 
+       /* Recalculate predicted_us based on prediction_history_pct */
+       data->predicted_us *= PRED_HISTORY_PCT;
+       data->predicted_us += (100 - PRED_HISTORY_PCT) *
+                               data->current_predicted_us;
+       data->predicted_us /= 100;
+
        /* find the deepest idle state that satisfies our constraints */
        for (i = CPUIDLE_DRIVER_STATE_START + 1; i < dev->state_count; i++) {
                struct cpuidle_state *s = &dev->states[i];
@@ -97,7 +105,7 @@ static void menu_reflect(struct cpuidle_device *dev)
                measured_us = -1;
 
        /* Predict time until next break event */
-       data->predicted_us = max(measured_us, data->last_measured_us);
+       data->current_predicted_us = max(measured_us, data->last_measured_us);
 
        if (last_idle_us + BREAK_FUZZ <
            data->expected_us - target->exit_latency) {