From 5bb1729cbdfbe974ad6385be94b14afbac97e19f Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Sat, 16 Jan 2016 00:56:34 +0100
Subject: [PATCH] cpuidle: menu: Avoid pointless checks in menu_select()
If menu_select() cannot find a suitable state to return, it will
return the state index stored in data->last_state_idx. This
means that it is pointless to look at the states whose indices
are less than or equal to data->last_state_idx in the main loop,
so don't do that.
Given that those checks are done on every idle state selection, this
change can save quite a bit of completely unnecessary overhead.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/cpuidle/governors/menu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index be0bae0b41e9b..0742b32966739 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -342,7 +342,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* Find the idle state with the lowest power while satisfying
* our constraints.
*/
- for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+ for (i = data->last_state_idx + 1; i < drv->state_count; i++) {
struct cpuidle_state *s = &drv->states[i];
struct cpuidle_state_usage *su = &dev->states_usage[i];
--
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