diff mbox

[V3,3/6] sched: idle: Get the next timer event and pass it the cpuidle framework

Message ID 1415370687-18688-4-git-send-email-daniel.lezcano@linaro.org
State New
Headers show

Commit Message

Daniel Lezcano Nov. 7, 2014, 2:31 p.m. UTC 
Following the logic of the previous patch, retrieve from the idle task the
expected timer sleep duration and pass it to the cpuidle framework.

Take the opportunity to remove the unused headers in the menu.c file.

This patch does not change the current behavior.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Len Brown <len.brown@intel.com>
---
 drivers/cpuidle/cpuidle.c          | 10 ++++------
 drivers/cpuidle/governors/ladder.c |  3 ++-
 drivers/cpuidle/governors/menu.c   |  8 ++------
 include/linux/cpuidle.h            |  8 +++++---
 kernel/sched/idle.c                | 13 +++++++++----
 5 files changed, 22 insertions(+), 20 deletions(-)

Comments

Preeti U Murthy Nov. 8, 2014, 10:44 a.m. UTC | #1 
On 11/07/2014 08:01 PM, Daniel Lezcano wrote:
> Following the logic of the previous patch, retrieve from the idle task the
> expected timer sleep duration and pass it to the cpuidle framework.
> 
> Take the opportunity to remove the unused headers in the menu.c file.
> 
> This patch does not change the current behavior.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Acked-by: Nicolas Pitre <nico@linaro.org>
> Reviewed-by: Len Brown <len.brown@intel.com>
> ---

This patch looks good to me as well.

Reviewed-by: Preeti U. Murthy
Peter Zijlstra Nov. 10, 2014, 12:43 p.m. UTC | #2 
On Fri, Nov 07, 2014 at 03:31:24PM +0100, Daniel Lezcano wrote:
>  static void cpu_idle_loop(void)
>  {
> -	unsigned int latency_req;
> +	unsigned int latency_req, next_timer_event;
>  
>  	while (1) {
>  		/*
> @@ -221,6 +222,9 @@ static void cpu_idle_loop(void)
>  
>  			latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
>  
> +			next_timer_event =
> +				ktime_to_us(tick_nohz_get_sleep_length());
> +
>  			/*
>  			 * In poll mode we reenable interrupts and spin.
>  			 *
> @@ -238,7 +242,8 @@ static void cpu_idle_loop(void)
>  			    tick_check_broadcast_expired())
>  				cpu_idle_poll();
>  			else
> -				cpuidle_idle_call(latency_req);
> +				cpuidle_idle_call(latency_req,
> +						  next_timer_event);
>  
>  			arch_cpu_idle_exit();
>  		}

Why do we want to query the next timer in the poll case? Afaict the
other patches don't make use of this either.
Daniel Lezcano Nov. 10, 2014, 3:15 p.m. UTC | #3 
On 11/10/2014 01:43 PM, Peter Zijlstra wrote:
> On Fri, Nov 07, 2014 at 03:31:24PM +0100, Daniel Lezcano wrote:
>>   static void cpu_idle_loop(void)
>>   {
>> -	unsigned int latency_req;
>> +	unsigned int latency_req, next_timer_event;
>>
>>   	while (1) {
>>   		/*
>> @@ -221,6 +222,9 @@ static void cpu_idle_loop(void)
>>
>>   			latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
>>
>> +			next_timer_event =
>> +				ktime_to_us(tick_nohz_get_sleep_length());
>> +
>>   			/*
>>   			 * In poll mode we reenable interrupts and spin.
>>   			 *
>> @@ -238,7 +242,8 @@ static void cpu_idle_loop(void)
>>   			    tick_check_broadcast_expired())
>>   				cpu_idle_poll();
>>   			else
>> -				cpuidle_idle_call(latency_req);
>> +				cpuidle_idle_call(latency_req,
>> +						  next_timer_event);
>>
>>   			arch_cpu_idle_exit();
>>   		}
>
> Why do we want to query the next timer in the poll case? Afaict the
> other patches don't make use of this either.

Well, the direction I am taking when writing those cleanups is to have 
something like:

"I will sleep X usec, I have Y usec latency constraints". Grouping the 
latency req and the next timer allows to stick to the next changes.
diff mbox

Patch

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 86f6cb8..f3e7b73 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -8,16 +8,12 @@ 
  * This code is licenced under the GPL.
  */
 
-#include <linux/clockchips.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
-#include <linux/sched.h>
 #include <linux/notifier.h>
 #include <linux/pm_qos.h>
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
-#include <linux/ktime.h>
-#include <linux/hrtimer.h>
 #include <linux/module.h>
 #include <trace/events/power.h>
 
@@ -156,11 +152,12 @@  int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  * @drv: the cpuidle driver
  * @dev: the cpuidle device
  * @latency_req: the latency constraint when choosing an idle state
+ * @next_timer_event: the duration until the timer expires
  *
  * Returns the index of the idle state.
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
-		   int latency_req)
+		   int latency_req, int next_timer_event)
 {
 	if (off || !initialized)
 		return -ENODEV;
@@ -171,7 +168,8 @@  int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	if (unlikely(use_deepest_state))
 		return cpuidle_find_deepest_state(drv, dev);
 
-	return cpuidle_curr_governor->select(drv, dev, latency_req);
+	return cpuidle_curr_governor->select(drv, dev, latency_req,
+					     next_timer_event);
 }
 
 /**
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 53113c2..51c9ccd 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -64,7 +64,8 @@  static inline void ladder_do_selection(struct ladder_device *ldev,
  * @dev: the CPU
  */
 static int ladder_select_state(struct cpuidle_driver *drv,
-			       struct cpuidle_device *dev, int latency_req)
+			       struct cpuidle_device *dev,
+			       int latency_req, int next_timer_event)
 {
 	struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
 	struct ladder_device_state *last_state;
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 9b7c0b9..91b3000 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -13,10 +13,6 @@ 
 #include <linux/kernel.h>
 #include <linux/cpuidle.h>
 #include <linux/pm_qos.h>
-#include <linux/time.h>
-#include <linux/ktime.h>
-#include <linux/hrtimer.h>
-#include <linux/tick.h>
 #include <linux/sched.h>
 #include <linux/math64.h>
 #include <linux/module.h>
@@ -288,7 +284,7 @@  again:
  * @dev: the CPU
  */
 static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
-		       int latency_req)
+		       int latency_req, int next_timer_event)
 {
 	struct menu_device *data = this_cpu_ptr(&menu_devices);
 	int i;
@@ -303,7 +299,7 @@  static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
 
 	/* determine the expected residency time, round up */
-	data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length());
+	data->next_timer_us = next_timer_event;
 
 	get_iowait_load(&nr_iowaiters, &cpu_load);
 	data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index fb465c1..d477746 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -122,7 +122,8 @@  struct cpuidle_driver {
 extern void disable_cpuidle(void);
 
 extern int cpuidle_select(struct cpuidle_driver *drv,
-			  struct cpuidle_device *dev, int latency_req);
+			  struct cpuidle_device *dev,
+			  int latency_req, int next_timer_event);
 extern int cpuidle_enter(struct cpuidle_driver *drv,
 			 struct cpuidle_device *dev, int index);
 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
@@ -150,7 +151,8 @@  extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
 #else
 static inline void disable_cpuidle(void) { }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
-				 struct cpuidle_device *dev, int latency_req)
+				 struct cpuidle_device *dev,
+				 int latency_req, int next_timer_event)
 {return -ENODEV; }
 static inline int cpuidle_enter(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev, int index)
@@ -206,7 +208,7 @@  struct cpuidle_governor {
 
 	int  (*select)		(struct cpuidle_driver *drv,
 				 struct cpuidle_device *dev,
-				 int latency_req);
+				 int latency_req, int next_timer_event);
 	void (*reflect)		(struct cpuidle_device *dev, int index);
 
 	struct module 		*owner;
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 189e80a..0a7a1d1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -80,7 +80,8 @@  static inline int cpu_idle_poll(void)
  * set, and it returns with polling set.  If it ever stops polling, it
  * must clear the polling bit.
  */
-static void cpuidle_idle_call(unsigned int latency_req)
+static void cpuidle_idle_call(unsigned int latency_req,
+			      unsigned int next_timer_event)
 {
 	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
@@ -113,7 +114,7 @@  static void cpuidle_idle_call(unsigned int latency_req)
 	 * Ask the cpuidle framework to choose a convenient idle state.
 	 * Fall back to the default arch idle method on errors.
 	 */
-	next_state = cpuidle_select(drv, dev, latency_req);
+	next_state = cpuidle_select(drv, dev, latency_req, next_timer_event);
 	if (next_state < 0) {
 use_default:
 		/*
@@ -194,7 +195,7 @@  exit_idle:
  */
 static void cpu_idle_loop(void)
 {
-	unsigned int latency_req;
+	unsigned int latency_req, next_timer_event;
 
 	while (1) {
 		/*
@@ -221,6 +222,9 @@  static void cpu_idle_loop(void)
 
 			latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
 
+			next_timer_event =
+				ktime_to_us(tick_nohz_get_sleep_length());
+
 			/*
 			 * In poll mode we reenable interrupts and spin.
 			 *
@@ -238,7 +242,8 @@  static void cpu_idle_loop(void)
 			    tick_check_broadcast_expired())
 				cpu_idle_poll();
 			else
-				cpuidle_idle_call(latency_req);
+				cpuidle_idle_call(latency_req,
+						  next_timer_event);
 
 			arch_cpu_idle_exit();
 		}