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[V2,3/4] x86,idle: Set residency to 0 if target Cstate not enter

Message ID 1350594744-22353-4-git-send-email-youquan.song@intel.com (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Youquan Song Oct. 18, 2012, 9:12 p.m. UTC 
When cpuidle governor choose a C-state to enter for idle CPU, but it notice that
there is tasks request to be executed. So the idle CPU will not really enter
the target C-state and go to run task.

In this situation, it will use the residency of previous really entered target 
C-states. Obviously, it is not reasonable. 

So, this patch fix it by set the target C-state residency to 0. 

Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
---
 drivers/cpuidle/cpuidle.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
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Patch

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index e28f6ea..01dca54 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -144,6 +144,10 @@  int cpuidle_idle_call(void)
 	/* ask the governor for the next state */
 	next_state = cpuidle_curr_governor->select(drv, dev);
 	if (need_resched()) {
+		dev->last_residency = 0;
+		/* give the governor an opportunity to reflect on the outcome */
+		if (cpuidle_curr_governor->reflect)
+			cpuidle_curr_governor->reflect(dev, next_state);
 		local_irq_enable();
 		return 0;
 	}