* [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency
@ 2019-11-13 18:54 Daniel Lezcano
2019-11-13 18:54 ` [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function Daniel Lezcano
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Daniel Lezcano @ 2019-11-13 18:54 UTC (permalink / raw)
To: rafael; +Cc: linux-pm, linux-kernel, ulf.hansson
We want to specify a latency constraint when choosing an idle state at
play_idle time. Instead of duplicating the information in the
structure or propagate the latency in the call stack, change the
use_deepest_state by use_latency to introduce this constraint.
A zero latency constraint means "do not use the deepest idle state
path" as the 'use_deepest_state' boolean was used in the
cpuidle_idle_call.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle.c | 6 +++---
include/linux/cpuidle.h | 6 +++---
kernel/sched/idle.c | 6 +++---
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 44ae39f2b47a..f68a6c9e8482 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -100,19 +100,19 @@ static int find_deepest_state(struct cpuidle_driver *drv,
/**
* cpuidle_use_deepest_state - Set/clear governor override flag.
- * @enable: New value of the flag.
+ * @latency: A latency constraint
*
* Set/unset the current CPU to use the deepest idle state (override governors
* going forward if set).
*/
-void cpuidle_use_deepest_state(bool enable)
+void cpuidle_use_latency(unsigned int latency)
{
struct cpuidle_device *dev;
preempt_disable();
dev = cpuidle_get_device();
if (dev)
- dev->use_deepest_state = enable;
+ dev->use_latency = latency;
preempt_enable();
}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index d23a3b1ddcf6..32018704f4ea 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -83,8 +83,8 @@ 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 use_latency;
unsigned int cpu;
ktime_t next_hrtimer;
@@ -210,7 +210,7 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
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_latency(unsigned int latency);
#else
static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
@@ -218,7 +218,7 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
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_latency(unsigned int latency)
{
}
#endif
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8dad5aa600ea..00e064d3dfe1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -165,7 +165,7 @@ 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_latency) {
if (idle_should_enter_s2idle()) {
rcu_idle_enter();
@@ -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_latency(1);
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_latency(0);
current->flags &= ~PF_IDLE;
preempt_fold_need_resched();
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function
2019-11-13 18:54 [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Daniel Lezcano
@ 2019-11-13 18:54 ` Daniel Lezcano
2019-11-13 22:08 ` Rafael J. Wysocki
2019-11-13 18:54 ` [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state Daniel Lezcano
2019-11-13 21:59 ` [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Rafael J. Wysocki
2 siblings, 1 reply; 6+ messages in thread
From: Daniel Lezcano @ 2019-11-13 18:54 UTC (permalink / raw)
To: rafael; +Cc: linux-pm, linux-kernel, ulf.hansson
By default the play_idle() function leads to the deepest idle state
selection which is not necessarily the state we are interested in when
forcing the CPU to go to idle.
Add a latency parameter to the play_idle() function, so the caller can
use the constraint to allow a shallower state.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/powercap/idle_inject.c | 2 +-
drivers/thermal/intel/intel_powerclamp.c | 2 +-
include/linux/cpu.h | 2 +-
kernel/sched/idle.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index cd1270614cc6..6f2bfb172e61 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -138,7 +138,7 @@ 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), UINT_MAX);
}
/**
diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c
index 53216dcbe173..dd1330d59176 100644
--- a/drivers/thermal/intel/intel_powerclamp.c
+++ b/drivers/thermal/intel/intel_powerclamp.c
@@ -430,7 +430,7 @@ 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), UINT_MAX);
balance:
if (clamping && w_data->clamping && cpu_online(w_data->cpu))
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index d0633ebdaa9c..241f558af17a 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, unsigned int latency);
#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 00e064d3dfe1..56a8b9d35cb9 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, unsigned int latency)
{
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_latency(1);
+ cpuidle_use_latency(latency);
it.done = 0;
hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function
2019-11-13 18:54 ` [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function Daniel Lezcano
@ 2019-11-13 22:08 ` Rafael J. Wysocki
0 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2019-11-13 22:08 UTC (permalink / raw)
To: Daniel Lezcano
Cc: Rafael J. Wysocki, Linux PM, Linux Kernel Mailing List, Ulf Hansson
On Wed, Nov 13, 2019 at 7:54 PM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> By default the play_idle() function leads to the deepest idle state
> selection which is not necessarily the state we are interested in when
> forcing the CPU to go to idle.
>
> Add a latency parameter to the play_idle() function, so the caller can
> use the constraint to allow a shallower state.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/powercap/idle_inject.c | 2 +-
> drivers/thermal/intel/intel_powerclamp.c | 2 +-
> include/linux/cpu.h | 2 +-
> kernel/sched/idle.c | 4 ++--
> 4 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
> index cd1270614cc6..6f2bfb172e61 100644
> --- a/drivers/powercap/idle_inject.c
> +++ b/drivers/powercap/idle_inject.c
> @@ -138,7 +138,7 @@ 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), UINT_MAX);
> }
>
> /**
> diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c
> index 53216dcbe173..dd1330d59176 100644
> --- a/drivers/thermal/intel/intel_powerclamp.c
> +++ b/drivers/thermal/intel/intel_powerclamp.c
> @@ -430,7 +430,7 @@ 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), UINT_MAX);
>
> balance:
> if (clamping && w_data->clamping && cpu_online(w_data->cpu))
> diff --git a/include/linux/cpu.h b/include/linux/cpu.h
> index d0633ebdaa9c..241f558af17a 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, unsigned int latency);
>
> #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 00e064d3dfe1..56a8b9d35cb9 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, unsigned int latency)
I'd rather rename this to something like play_idle_precise() and
redefine play_idle() as a single-argument wrapper around it.
Maybe also change the first arg to ns while at it (and keep us in play_idle())?
> {
> 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_latency(1);
> + cpuidle_use_latency(latency);
>
> it.done = 0;
> hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state
2019-11-13 18:54 [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Daniel Lezcano
2019-11-13 18:54 ` [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function Daniel Lezcano
@ 2019-11-13 18:54 ` Daniel Lezcano
2019-11-13 22:19 ` Rafael J. Wysocki
2019-11-13 21:59 ` [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Rafael J. Wysocki
2 siblings, 1 reply; 6+ messages in thread
From: Daniel Lezcano @ 2019-11-13 18:54 UTC (permalink / raw)
To: rafael; +Cc: linux-pm, linux-kernel, ulf.hansson
As the dev->use_latency is filled with the latency value when this
function is called, use it as a parameter to the
find_deepest_idle_state() function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index f68a6c9e8482..659d8b1ece6d 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -124,7 +124,7 @@ void cpuidle_use_latency(unsigned int latency)
int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{
- return find_deepest_state(drv, dev, UINT_MAX, 0, false);
+ return find_deepest_state(drv, dev, dev->use_latency, 0, false);
}
#ifdef CONFIG_SUSPEND
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state
2019-11-13 18:54 ` [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state Daniel Lezcano
@ 2019-11-13 22:19 ` Rafael J. Wysocki
0 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2019-11-13 22:19 UTC (permalink / raw)
To: Daniel Lezcano
Cc: Rafael J. Wysocki, Linux PM, Linux Kernel Mailing List, Ulf Hansson
On Wed, Nov 13, 2019 at 7:54 PM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> As the dev->use_latency is filled with the latency value when this
> function is called, use it as a parameter to the
> find_deepest_idle_state() function.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/cpuidle/cpuidle.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index f68a6c9e8482..659d8b1ece6d 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -124,7 +124,7 @@ void cpuidle_use_latency(unsigned int latency)
> int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
> struct cpuidle_device *dev)
> {
> - return find_deepest_state(drv, dev, UINT_MAX, 0, false);
> + return find_deepest_state(drv, dev, dev->use_latency, 0, false);
This breaks the suspend-to-idle case when ->enter_s2idle is NULL for
all of the enabled states, because the latency limit for forced idle
should not be applied then.
Maybe pass the latency limit to cpuidle_find_deepest_state() and
rearrange the code in cpuidle_idle_call() to use U64_MAX in the s2idle
case.
BTW, note that find_deepest_state() will take a u64 latency limit in
ns now (and going forward).
> }
>
> #ifdef CONFIG_SUSPEND
> --
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency
2019-11-13 18:54 [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Daniel Lezcano
2019-11-13 18:54 ` [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function Daniel Lezcano
2019-11-13 18:54 ` [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state Daniel Lezcano
@ 2019-11-13 21:59 ` Rafael J. Wysocki
2 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2019-11-13 21:59 UTC (permalink / raw)
To: Daniel Lezcano
Cc: Rafael J. Wysocki, Linux PM, Linux Kernel Mailing List, Ulf Hansson
On Wed, Nov 13, 2019 at 7:54 PM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> We want to specify a latency constraint when choosing an idle state at
> play_idle time. Instead of duplicating the information in the
> structure or propagate the latency in the call stack, change the
> use_deepest_state by use_latency to introduce this constraint.
>
> A zero latency constraint means "do not use the deepest idle state
> path" as the 'use_deepest_state' boolean was used in the
> cpuidle_idle_call.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/cpuidle/cpuidle.c | 6 +++---
> include/linux/cpuidle.h | 6 +++---
> kernel/sched/idle.c | 6 +++---
> 3 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 44ae39f2b47a..f68a6c9e8482 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -100,19 +100,19 @@ static int find_deepest_state(struct cpuidle_driver *drv,
>
> /**
> * cpuidle_use_deepest_state - Set/clear governor override flag.
> - * @enable: New value of the flag.
> + * @latency: A latency constraint
I would call this latency_limit.
Maybe even latency_limit_ns (or us, whatever is more suitable), to
make it clear which unit of time is used here.
> *
> * Set/unset the current CPU to use the deepest idle state (override governors
> * going forward if set).
I would update the comment too, something like:
"Set/unset the current CPU to use the deepest idle state with the exit
latency within @latency_limit"
> */
> -void cpuidle_use_deepest_state(bool enable)
> +void cpuidle_use_latency(unsigned int latency)
I wouldn't change the name of the function (because why really?).
> {
> struct cpuidle_device *dev;
>
> preempt_disable();
> dev = cpuidle_get_device();
> if (dev)
> - dev->use_deepest_state = enable;
> + dev->use_latency = latency;
> preempt_enable();
> }
>
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index d23a3b1ddcf6..32018704f4ea 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -83,8 +83,8 @@ 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 use_latency;
And maybe call this forced_idle_latency_limit or similar?
The idea being that when it is set, idle is forced (i.e. no
governors), but there is a latency limit for the state to use.
> unsigned int cpu;
> ktime_t next_hrtimer;
>
> @@ -210,7 +210,7 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
> struct cpuidle_device *dev);
> 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_latency(unsigned int latency);
> #else
> static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
> struct cpuidle_device *dev)
> @@ -218,7 +218,7 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
> 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_latency(unsigned int latency)
> {
> }
> #endif
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index 8dad5aa600ea..00e064d3dfe1 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -165,7 +165,7 @@ 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_latency) {
> if (idle_should_enter_s2idle()) {
> rcu_idle_enter();
>
> @@ -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_latency(1);
>
> 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_latency(0);
> current->flags &= ~PF_IDLE;
>
> preempt_fold_need_resched();
> --
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-11-13 22:20 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-11-13 18:54 [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Daniel Lezcano
2019-11-13 18:54 ` [PATCH RFC 2/3] sched: idle: Add a latency parameter to the play_idle function Daniel Lezcano
2019-11-13 22:08 ` Rafael J. Wysocki
2019-11-13 18:54 ` [PATCH RFC 3/3] cpuidle: Use the latency to call find_deepest_idle_state Daniel Lezcano
2019-11-13 22:19 ` Rafael J. Wysocki
2019-11-13 21:59 ` [PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency Rafael J. Wysocki
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