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authorDeepthi Dharwar <deepthi@linux.vnet.ibm.com>2011-10-28 16:20:09 +0530
committerLen Brown <len.brown@intel.com>2011-11-06 21:13:30 -0500
commite978aa7d7d57d04eb5f88a7507c4fb98577def77 (patch)
treed6d6dfe1dba4d4749c7eafe348351aa499c3c5eb /drivers/cpuidle/cpuidle.c
parentc3b92c8787367a8bb53d57d9789b558f1295cc96 (diff)
downloadlinux-linaro-stable-e978aa7d7d57d04eb5f88a7507c4fb98577def77.tar.gz
cpuidle: Move dev->last_residency update to driver enter routine; remove dev->last_state
Cpuidle governor only suggests the state to enter using the governor->select() interface, but allows the low level driver to override the recommended state. The actual entered state may be different because of software or hardware demotion. Software demotion is done by the back-end cpuidle driver and can be accounted correctly. Current cpuidle code uses last_state field to capture the actual state entered and based on that updates the statistics for the state entered. Ideally the driver enter routine should update the counters, and it should return the state actually entered rather than the time spent there. The generic cpuidle code should simply handle where the counters live in the sysfs namespace, not updating the counters. Reference: https://lkml.org/lkml/2011/3/25/52 Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com> Tested-by: Jean Pihet <j-pihet@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle.c')
-rw-r--r--drivers/cpuidle/cpuidle.c32
1 files changed, 16 insertions, 16 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index d4c542372886..88bd12104396 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -62,7 +62,7 @@ int cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_state *target_state;
- int next_state;
+ int next_state, entered_state;
if (off)
return -ENODEV;
@@ -102,26 +102,27 @@ int cpuidle_idle_call(void)
target_state = &dev->states[next_state];
- /* enter the state and update stats */
- dev->last_state = target_state;
-
trace_power_start(POWER_CSTATE, next_state, dev->cpu);
trace_cpu_idle(next_state, dev->cpu);
- dev->last_residency = target_state->enter(dev, target_state);
+ entered_state = target_state->enter(dev, next_state);
trace_power_end(dev->cpu);
trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu);
- if (dev->last_state)
- target_state = dev->last_state;
-
- target_state->time += (unsigned long long)dev->last_residency;
- target_state->usage++;
+ if (entered_state >= 0) {
+ /* Update cpuidle counters */
+ /* This can be moved to within driver enter routine
+ * but that results in multiple copies of same code.
+ */
+ dev->states[entered_state].time +=
+ (unsigned long long)dev->last_residency;
+ dev->states[entered_state].usage++;
+ }
/* give the governor an opportunity to reflect on the outcome */
if (cpuidle_curr_governor->reflect)
- cpuidle_curr_governor->reflect(dev);
+ cpuidle_curr_governor->reflect(dev, entered_state);
return 0;
}
@@ -172,11 +173,10 @@ void cpuidle_resume_and_unlock(void)
EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
#ifdef CONFIG_ARCH_HAS_CPU_RELAX
-static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
+static int poll_idle(struct cpuidle_device *dev, int index)
{
ktime_t t1, t2;
s64 diff;
- int ret;
t1 = ktime_get();
local_irq_enable();
@@ -188,8 +188,9 @@ static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
if (diff > INT_MAX)
diff = INT_MAX;
- ret = (int) diff;
- return ret;
+ dev->last_residency = (int) diff;
+
+ return index;
}
static void poll_idle_init(struct cpuidle_device *dev)
@@ -248,7 +249,6 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
dev->states[i].time = 0;
}
dev->last_residency = 0;
- dev->last_state = NULL;
smp_wmb();