The patch titled
cpuidle: menu governor: reduce latency on exit
has been added to the -mm tree. Its filename is
cpuidle-menu-governor-reduce-latency-on-exit.patch
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------------------------------------------------------
Subject: cpuidle: menu governor: reduce latency on exit
From: Corrado Zoccolo <czoccolo@xxxxxxxxx>
Move the state residency accounting and statistics computation off the hot
exit path.
On exit, the need to recompute statistics is recorded, and new statistics
will be computed when menu_select is called again.
Signed-off-by: Corrado Zoccolo <czoccolo@xxxxxxxxx>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Adam Belay <abelay@xxxxxxxxxx
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/cpuidle/governors/menu.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff -puN drivers/cpuidle/governors/menu.c~cpuidle-menu-governor-reduce-latency-on-exit drivers/cpuidle/governors/menu.c
--- a/drivers/cpuidle/governors/menu.c~cpuidle-menu-governor-reduce-latency-on-exit
+++ a/drivers/cpuidle/governors/menu.c
@@ -19,6 +19,7 @@
struct menu_device {
int last_state_idx;
+ int needs_update;
unsigned int expected_us;
unsigned int predicted_us;
@@ -29,6 +30,8 @@ struct menu_device {
static DEFINE_PER_CPU(struct menu_device, menu_devices);
+static void menu_update(struct cpuidle_device *dev);
+
/**
* menu_select - selects the next idle state to enter
* @dev: the CPU
@@ -39,6 +42,11 @@ static int menu_select(struct cpuidle_de
int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
int i;
+ if (data->needs_update) {
+ menu_update(dev);
+ data->needs_update = 0;
+ }
+
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0)) {
data->last_state_idx = 0;
@@ -72,7 +80,7 @@ static int menu_select(struct cpuidle_de
}
/**
- * menu_reflect - attempts to guess what happened after entry
+ * menu_reflect - records that data structures need update
* @dev: the CPU
*
* NOTE: it's important to be fast here because this operation will add to
@@ -81,6 +89,16 @@ static int menu_select(struct cpuidle_de
static void menu_reflect(struct cpuidle_device *dev)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
+ data->needs_update = 1;
+}
+
+/**
+ * menu_update - attempts to guess what happened after entry
+ * @dev: the CPU
+ */
+static void menu_update(struct cpuidle_device *dev)
+{
+ struct menu_device *data = &__get_cpu_var(menu_devices);
int last_idx = data->last_state_idx;
unsigned int last_idle_us = cpuidle_get_last_residency(dev);
struct cpuidle_state *target = &dev->states[last_idx];
_
Patches currently in -mm which might be from czoccolo@xxxxxxxxx are
cpuidle-menu-governor-reduce-latency-on-exit.patch
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