linux-kernel - [PATCH 1/7] Cpuidle: rename expected_us to next_timer

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Date:	Mon, 24 Feb 2014 08:29:31 +0200
From:	Tuukka Tikkanen <tuukka.tikkanen@...aro.org>
To:	linux-pm@...r.kernel.org, rjw@...ysocki.net
Cc:	daniel.lezcano@...aro.org, tuukka.tikkanen@...aro.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/7] Cpuidle: rename expected_us to next_timer_us in menu governor

The field expected_us is used to store the time remaining until next
timer expiry. The name is inaccurate, as we really do not expect all
wakeups to be caused by timers. In addition, another field with a very
similar name (predicted_us) is used to store the predicted time
remaining until any wakeup source being active.

This patch renames expected_us to next_timer_us in order to better
reflect the contained information.

Signed-off-by: Tuukka Tikkanen <tuukka.tikkanen@...aro.org>
---
 drivers/cpuidle/governors/menu.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index cf7f2f0..e9a2a27 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -122,7 +122,7 @@ struct menu_device {
 	int		last_state_idx;
 	int             needs_update;
 
-	unsigned int	expected_us;
+	unsigned int	next_timer_us;
 	unsigned int	predicted_us;
 	unsigned int	exit_us;
 	unsigned int	bucket;
@@ -257,7 +257,7 @@ again:
 		stddev = int_sqrt(stddev);
 		if (((avg > stddev * 6) && (divisor * 4 >= INTERVALS * 3))
 							|| stddev <= 20) {
-			if (data->expected_us > avg)
+			if (data->next_timer_us > avg)
 				data->predicted_us = avg;
 			return;
 		}
@@ -306,11 +306,11 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 
 	/* determine the expected residency time, round up */
 	t = ktime_to_timespec(tick_nohz_get_sleep_length());
-	data->expected_us =
+	data->next_timer_us =
 		t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
 
 
-	data->bucket = which_bucket(data->expected_us);
+	data->bucket = which_bucket(data->next_timer_us);
 
 	multiplier = performance_multiplier();
 
@@ -326,7 +326,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 	 * operands are 32 bits.
 	 * Make sure to round up for half microseconds.
 	 */
-	data->predicted_us = div_round64((uint64_t)data->expected_us *
+	data->predicted_us = div_round64((uint64_t)data->next_timer_us *
 					 data->correction_factor[data->bucket],
 					 RESOLUTION * DECAY);
 
@@ -336,7 +336,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 	 * We want to default to C1 (hlt), not to busy polling
 	 * unless the timer is happening really really soon.
 	 */
-	if (data->expected_us > 5 &&
+	if (data->next_timer_us > 5 &&
 	    !drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
 		dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
 		data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
@@ -401,7 +401,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 	 * for the whole expected time.
 	 */
 	if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID)))
-		last_idle_us = data->expected_us;
+		last_idle_us = data->next_timer_us;
 
 
 	measured_us = last_idle_us;
@@ -418,8 +418,8 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 	new_factor = data->correction_factor[data->bucket];
 	new_factor -= new_factor / DECAY;
 
-	if (data->expected_us > 0 && measured_us < MAX_INTERESTING)
-		new_factor += RESOLUTION * measured_us / data->expected_us;
+	if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING)
+		new_factor += RESOLUTION * measured_us / data->next_timer_us;
 	else
 		/*
 		 * we were idle so long that we count it as a perfect
-- 
1.7.9.5

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