[PATCH V2 1/3] cpuidle: play_idle: Make play_idle more flexible

[PATCH V2 1/3] cpuidle: play_idle: Make play_idle more flexible

[Daniel Lezcano]

The play_idle function has two users, the intel powerclamp and the
idle_injection.

The idle injection cooling device uses the function via the
idle_injection powercap's APIs. Unfortunately, play_idle is currently
limited by the idle state depth: by default the deepest idle state is
selected. On the ARM[64] platforms, most of the time it is the cluster
idle state, the exit latency and the residency can be very high. That
reduces the scope of the idle injection usage because the impact on
the performances can be very significant.

If the idle injection cycles can be done with a shallow state like a
retention state, the cooling effect would eventually give similar
results than the cpufreq cooling device.

In order to prepare the function to receive an idle state parameter,
let's replace the 'use_deepest_state' boolean field with 'use_state'
and use this value to enter the specific idle state.

The current code keeps the default behavior which is go to the deepest
idle state.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/cpuidle/cpuidle.c | 21 +++++++++++----------
 include/linux/cpuidle.h   | 13 ++++++-------
 kernel/sched/idle.c       | 10 +++++-----
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 0895b988fa92..f8b54f277589 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -99,31 +99,31 @@ static int find_deepest_state(struct cpuidle_driver *drv,
 }
 
 /**
- * cpuidle_use_deepest_state - Set/clear governor override flag.
- * @enable: New value of the flag.
+ * cpuidle_use_state - Force the cpuidle framework to enter an idle state.
+ * @state: An integer for an idle state
  *
- * Set/unset the current CPU to use the deepest idle state (override governors
- * going forward if set).
+ * Specify an idle state the cpuidle framework must step in and bypass
+ * the idle state selection process.
  */
-void cpuidle_use_deepest_state(bool enable)
+void cpuidle_use_state(int state)
 {
 	struct cpuidle_device *dev;
 
 	preempt_disable();
 	dev = cpuidle_get_device();
 	if (dev)
-		dev->use_deepest_state = enable;
+		dev->use_state = state;
 	preempt_enable();
 }
 
 /**
  * cpuidle_find_deepest_state - Find the deepest available idle state.
- * @drv: cpuidle driver for the given CPU.
- * @dev: cpuidle device for the given CPU.
  */
-int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
-			       struct cpuidle_device *dev)
+int cpuidle_find_deepest_state(void)
 {
+	struct cpuidle_device *dev = cpuidle_get_device();
+	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
 	return find_deepest_state(drv, dev, UINT_MAX, 0, false);
 }
 
@@ -554,6 +554,7 @@ static void __cpuidle_unregister_device(struct cpuidle_device *dev)
 static void __cpuidle_device_init(struct cpuidle_device *dev)
 {
 	memset(dev->states_usage, 0, sizeof(dev->states_usage));
+	dev->use_state = CPUIDLE_STATE_NOUSE;
 	dev->last_residency = 0;
 	dev->next_hrtimer = 0;
 }
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 2dc4c6b19c25..ba0751b26e37 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -15,6 +15,7 @@
 #include <linux/list.h>
 #include <linux/hrtimer.h>
 
+#define CPUIDLE_STATE_NOUSE	-1
 #define CPUIDLE_STATE_MAX	10
 #define CPUIDLE_NAME_LEN	16
 #define CPUIDLE_DESC_LEN	32
@@ -80,11 +81,11 @@ struct cpuidle_driver_kobj;
 struct cpuidle_device {
 	unsigned int		registered:1;
 	unsigned int		enabled:1;
-	unsigned int		use_deepest_state:1;
 	unsigned int		poll_time_limit:1;
 	unsigned int		cpu;
 	ktime_t			next_hrtimer;
 
+	int			use_state;
 	int			last_state_idx;
 	int			last_residency;
 	u64			poll_limit_ns;
@@ -203,19 +204,17 @@ static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
 #endif
 
 #ifdef CONFIG_CPU_IDLE
-extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
-				      struct cpuidle_device *dev);
+extern int cpuidle_find_deepest_state(void);
 extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev);
-extern void cpuidle_use_deepest_state(bool enable);
+extern void cpuidle_use_state(int state);
 #else
-static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
-					     struct cpuidle_device *dev)
+static inline int cpuidle_find_deepest_state(void)
 {return -ENODEV; }
 static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
 				       struct cpuidle_device *dev)
 {return -ENODEV; }
-static inline void cpuidle_use_deepest_state(bool enable)
+static inline void cpuidle_use_state(int state)
 {
 }
 #endif
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index b98283fc6914..17da9cb309e1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -165,7 +165,8 @@ static void cpuidle_idle_call(void)
 	 * until a proper wakeup interrupt happens.
 	 */
 
-	if (idle_should_enter_s2idle() || dev->use_deepest_state) {
+	if (idle_should_enter_s2idle() ||
+	    dev->use_state != CPUIDLE_STATE_NOUSE) {
 		if (idle_should_enter_s2idle()) {
 			rcu_idle_enter();
 
@@ -181,8 +182,7 @@ static void cpuidle_idle_call(void)
 		tick_nohz_idle_stop_tick();
 		rcu_idle_enter();
 
-		next_state = cpuidle_find_deepest_state(drv, dev);
-		call_cpuidle(drv, dev, next_state);
+		call_cpuidle(drv, dev, dev->use_state);
 	} else {
 		bool stop_tick = true;
 
@@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us)
 	rcu_sleep_check();
 	preempt_disable();
 	current->flags |= PF_IDLE;
-	cpuidle_use_deepest_state(true);
+	cpuidle_use_state(cpuidle_find_deepest_state());
 
 	it.done = 0;
 	hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@@ -339,7 +339,7 @@ void play_idle(unsigned long duration_us)
 	while (!READ_ONCE(it.done))
 		do_idle();
 
-	cpuidle_use_deepest_state(false);
+	cpuidle_use_state(CPUIDLE_STATE_NOUSE);
 	current->flags &= ~PF_IDLE;
 
 	preempt_fold_need_resched();
-- 
2.17.1

[PATCH V2 2/3] cpuidle: play_idle: Specify play_idle with an idle state

[Daniel Lezcano]

Currently, the play_idle function does not allow to tell which idle
state we want to go. Improve this by passing the idle state as
parameter to the function.

There is no functional changes, the cpuidle state is the deepest one.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/powercap/idle_inject.c           | 3 ++-
 drivers/thermal/intel/intel_powerclamp.c | 4 +++-
 include/linux/cpu.h                      | 2 +-
 kernel/sched/idle.c                      | 4 ++--
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index cd1270614cc6..9b18667b9f26 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -138,7 +138,8 @@ static void idle_inject_fn(unsigned int cpu)
 	 */
 	iit->should_run = 0;
 
-	play_idle(READ_ONCE(ii_dev->idle_duration_us));
+	play_idle(READ_ONCE(ii_dev->idle_duration_us),
+		  cpuidle_find_deepest_state());
 }
 
 /**
diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c
index 53216dcbe173..b55786c169ae 100644
--- a/drivers/thermal/intel/intel_powerclamp.c
+++ b/drivers/thermal/intel/intel_powerclamp.c
@@ -29,6 +29,7 @@
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/cpu.h>
+#include <linux/cpuidle.h>
 #include <linux/thermal.h>
 #include <linux/slab.h>
 #include <linux/tick.h>
@@ -430,7 +431,8 @@ static void clamp_idle_injection_func(struct kthread_work *work)
 	if (should_skip)
 		goto balance;
 
-	play_idle(jiffies_to_usecs(w_data->duration_jiffies));
+	play_idle(jiffies_to_usecs(w_data->duration_jiffies),
+		  cpuidle_find_deepest_state());
 
 balance:
 	if (clamping && w_data->clamping && cpu_online(w_data->cpu))
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 88dc0c653925..76e3038b63ce 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -179,7 +179,7 @@ void arch_cpu_idle_dead(void);
 int cpu_report_state(int cpu);
 int cpu_check_up_prepare(int cpu);
 void cpu_set_state_online(int cpu);
-void play_idle(unsigned long duration_us);
+void play_idle(unsigned long duration_us, int state);
 
 #ifdef CONFIG_HOTPLUG_CPU
 bool cpu_wait_death(unsigned int cpu, int seconds);
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 17da9cb309e1..ead439dab2b5 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -311,7 +311,7 @@ static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-void play_idle(unsigned long duration_us)
+void play_idle(unsigned long duration_us, int state)
 {
 	struct idle_timer it;
 
@@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us)
 	rcu_sleep_check();
 	preempt_disable();
 	current->flags |= PF_IDLE;
-	cpuidle_use_state(cpuidle_find_deepest_state());
+	cpuidle_use_state(state);
 
 	it.done = 0;
 	hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-- 
2.17.1

[PATCH V2 3/3] powercap/drivers/idle_inject: Specify the idle state to inject

[Daniel Lezcano]

Currently the idle injection framework only allows to inject the
deepest idle state available on the system.

Give the opportunity to specify which idle state we want to inject by
adding a new function helper to set the state and use it when calling
play_idle().

There is no functional changes, the cpuidle state is the deepest one.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/powercap/idle_inject.c | 15 ++++++++++++++-
 include/linux/idle_inject.h    |  3 +++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index 9b18667b9f26..a612c425d74c 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -38,6 +38,7 @@
 #define pr_fmt(fmt) "ii_dev: " fmt
 
 #include <linux/cpu.h>
+#include <linux/cpuidle.h>
 #include <linux/hrtimer.h>
 #include <linux/kthread.h>
 #include <linux/sched.h>
@@ -65,6 +66,7 @@ struct idle_inject_thread {
  */
 struct idle_inject_device {
 	struct hrtimer timer;
+	int state;
 	unsigned int idle_duration_us;
 	unsigned int run_duration_us;
 	unsigned long int cpumask[0];
@@ -139,7 +141,7 @@ static void idle_inject_fn(unsigned int cpu)
 	iit->should_run = 0;
 
 	play_idle(READ_ONCE(ii_dev->idle_duration_us),
-		  cpuidle_find_deepest_state());
+		  READ_ONCE(ii_dev->state));
 }
 
 /**
@@ -170,6 +172,16 @@ void idle_inject_get_duration(struct idle_inject_device *ii_dev,
 	*idle_duration_us = READ_ONCE(ii_dev->idle_duration_us);
 }
 
+/**
+ * idle_inject_set_state - set the idle state to inject
+ * @state: an integer for the idle state to inject
+ */
+void idle_inject_set_state(struct idle_inject_device *ii_dev, int state)
+{
+	if (state >= CPUIDLE_STATE_NOUSE && state < CPUIDLE_STATE_MAX)
+		WRITE_ONCE(ii_dev->state, state);
+}
+
 /**
  * idle_inject_start - start idle injections
  * @ii_dev: idle injection control device structure
@@ -298,6 +310,7 @@ struct idle_inject_device *idle_inject_register(struct cpumask *cpumask)
 	cpumask_copy(to_cpumask(ii_dev->cpumask), cpumask);
 	hrtimer_init(&ii_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	ii_dev->timer.function = idle_inject_timer_fn;
+	ii_dev->state = cpuidle_find_deepest_state();
 
 	for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {
 
diff --git a/include/linux/idle_inject.h b/include/linux/idle_inject.h
index a445cd1a36c5..e2b26b9ccd34 100644
--- a/include/linux/idle_inject.h
+++ b/include/linux/idle_inject.h
@@ -26,4 +26,7 @@ void idle_inject_set_duration(struct idle_inject_device *ii_dev,
 void idle_inject_get_duration(struct idle_inject_device *ii_dev,
 				 unsigned int *run_duration_us,
 				 unsigned int *idle_duration_us);
+
+void idle_inject_set_state(struct idle_inject_device *ii_dev, int state);
+
 #endif /* __IDLE_INJECT_H__ */
-- 
2.17.1

Re: [PATCH V2 2/3] cpuidle: play_idle: Specify play_idle with an idle state

[kbuild test robot]

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Hi Daniel,

I love your patch! Yet something to improve:

[auto build test ERROR on pm/linux-next]
[cannot apply to v5.4-rc1 next-20191002]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Daniel-Lezcano/cpuidle-play_idle-Make-play_idle-more-flexible/20191003-171142
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: x86_64-lkp (attached as .config)
compiler: gcc-7 (Debian 7.4.0-13) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> ERROR: "cpuidle_find_deepest_state" [drivers/thermal/intel/intel_powerclamp.ko] undefined!

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH V2 2/3] cpuidle: play_idle: Specify play_idle with an idle state

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2455 bytes --]

Hi Daniel,

I love your patch! Yet something to improve:

[auto build test ERROR on pm/linux-next]
[cannot apply to v5.4-rc1 next-20191003]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Daniel-Lezcano/cpuidle-play_idle-Make-play_idle-more-flexible/20191003-171142
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-13) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

Note: the linux-review/Daniel-Lezcano/cpuidle-play_idle-Make-play_idle-more-flexible/20191003-171142 HEAD 67d70fb96ed26998f13be3c91ed6cc5440390408 builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

   drivers/powercap/idle_inject.c: In function 'idle_inject_fn':
>> drivers/powercap/idle_inject.c:142:5: error: implicit declaration of function 'cpuidle_find_deepest_state'; did you mean 'cpu_report_state'? [-Werror=implicit-function-declaration]
        cpuidle_find_deepest_state());
        ^~~~~~~~~~~~~~~~~~~~~~~~~~
        cpu_report_state
   cc1: some warnings being treated as errors

vim +142 drivers/powercap/idle_inject.c

   120	
   121	/**
   122	 * idle_inject_fn - idle injection work function
   123	 * @cpu: the CPU owning the task
   124	 *
   125	 * This function calls play_idle() to inject a specified amount of CPU idle
   126	 * time.
   127	 */
   128	static void idle_inject_fn(unsigned int cpu)
   129	{
   130		struct idle_inject_device *ii_dev;
   131		struct idle_inject_thread *iit;
   132	
   133		ii_dev = per_cpu(idle_inject_device, cpu);
   134		iit = per_cpu_ptr(&idle_inject_thread, cpu);
   135	
   136		/*
   137		 * Let the smpboot main loop know that the task should not run again.
   138		 */
   139		iit->should_run = 0;
   140	
   141		play_idle(READ_ONCE(ii_dev->idle_duration_us),
 > 142			  cpuidle_find_deepest_state());
   143	}
   144	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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