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Subject[PATCH] cpuidle: enter_state: Don't needlessly calculate diff time
Date
ktime_us_delta() is not that cheap on some platform,
and I think this is also the right thing to do.
While at it, fix some coding style as well.

Signed-off-by: Fieah Lim <kw@fieahl.im>
---
drivers/cpuidle/cpuidle.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 6df894d65d9e..5f6b2c9b6555 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -247,21 +247,20 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
if (!cpuidle_state_is_coupled(drv, index))
local_irq_enable();

- diff = ktime_us_delta(time_end, time_start);
- if (diff > INT_MAX)
- diff = INT_MAX;
-
- dev->last_residency = (int) diff;
+ dev->last_residency = 0;

if (entered_state >= 0) {
- /* Update cpuidle counters */
- /* This can be moved to within driver enter routine
+ /* Update cpuidle counters
+ * This can be moved to within driver enter routine,
* but that results in multiple copies of same code.
*/
+ diff = ktime_us_delta(time_end, time_start);
+ if (diff > INT_MAX)
+ diff = INT_MAX;
+
+ dev->last_residency = (int)diff;
dev->states_usage[entered_state].time += dev->last_residency;
dev->states_usage[entered_state].usage++;
- } else {
- dev->last_residency = 0;
}

return entered_state;
--
2.18.0
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