From 99e98d3fb1008ef7416e16a1fd355cb73a253502 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 4 Nov 2019 12:16:17 +0100 Subject: cpuidle: Consolidate disabled state checks There are two reasons why CPU idle states may be disabled: either because the driver has disabled them or because they have been disabled by user space via sysfs. In the former case, the state's "disabled" flag is set once during the initialization of the driver and it is never cleared later (it is read-only effectively). In the latter case, the "disable" field of the given state's cpuidle_state_usage struct is set and it may be changed via sysfs. Thus checking whether or not an idle state has been disabled involves reading these two flags every time. In order to avoid the additional check of the state's "disabled" flag (which is effectively read-only anyway), use the value of it at the init time to set a (new) flag in the "disable" field of that state's cpuidle_state_usage structure and use the sysfs interface to manipulate another (new) flag in it. This way the state is disabled whenever the "disable" field of its cpuidle_state_usage structure is nonzero, whatever the reason, and it is the only place to look into to check whether or not the state has been disabled. Signed-off-by: Rafael J. Wysocki Acked-by: Daniel Lezcano Acked-by: Peter Zijlstra (Intel) --- include/linux/cpuidle.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 4b6b5bea8f79..d23a3b1ddcf6 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -29,6 +29,9 @@ struct cpuidle_driver; * CPUIDLE DEVICE INTERFACE * ****************************/ +#define CPUIDLE_STATE_DISABLED_BY_USER BIT(0) +#define CPUIDLE_STATE_DISABLED_BY_DRIVER BIT(1) + struct cpuidle_state_usage { unsigned long long disable; unsigned long long usage; -- cgit v1.2.3 From c1d51f684c72b5eb2aecbbd47be3a2977a2dc903 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 7 Nov 2019 15:25:12 +0100 Subject: cpuidle: Use nanoseconds as the unit of time Currently, the cpuidle subsystem uses microseconds as the unit of time which (among other things) causes the idle loop to incur some integer division overhead for no clear benefit. In order to allow cpuidle to measure time in nanoseconds, add two new fields, exit_latency_ns and target_residency_ns, to represent the exit latency and target residency of an idle state in nanoseconds, respectively, to struct cpuidle_state and initialize them with the help of the corresponding values in microseconds provided by drivers. Additionally, change cpuidle_governor_latency_req() to return the idle state exit latency constraint in nanoseconds. Also meeasure idle state residency (last_residency_ns in struct cpuidle_device and time_ns in struct cpuidle_driver) in nanoseconds and update the cpuidle core and governors accordingly. However, the menu governor still computes typical intervals in microseconds to avoid integer overflows. Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Acked-by: Doug Smythies Tested-by: Doug Smythies --- include/linux/cpuidle.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index d23a3b1ddcf6..22602747f468 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -35,7 +35,7 @@ struct cpuidle_driver; struct cpuidle_state_usage { unsigned long long disable; unsigned long long usage; - unsigned long long time; /* in US */ + u64 time_ns; unsigned long long above; /* Number of times it's been too deep */ unsigned long long below; /* Number of times it's been too shallow */ #ifdef CONFIG_SUSPEND @@ -48,6 +48,8 @@ struct cpuidle_state { char name[CPUIDLE_NAME_LEN]; char desc[CPUIDLE_DESC_LEN]; + u64 exit_latency_ns; + u64 target_residency_ns; unsigned int flags; unsigned int exit_latency; /* in US */ int power_usage; /* in mW */ @@ -89,7 +91,7 @@ struct cpuidle_device { ktime_t next_hrtimer; int last_state_idx; - int last_residency; + u64 last_residency_ns; u64 poll_limit_ns; struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX]; struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX]; @@ -263,7 +265,7 @@ struct cpuidle_governor { #ifdef CONFIG_CPU_IDLE extern int cpuidle_register_governor(struct cpuidle_governor *gov); -extern int cpuidle_governor_latency_req(unsigned int cpu); +extern s64 cpuidle_governor_latency_req(unsigned int cpu); #else static inline int cpuidle_register_governor(struct cpuidle_governor *gov) {return 0;} -- cgit v1.2.3 From cbda56d5fefcebc01448982a55836c88a825b34c Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 18 Nov 2019 12:11:24 +0100 Subject: cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks Commit 99e98d3fb100 ("cpuidle: Consolidate disabled state checks") overlooked the fact that the imx6q and tegra20 cpuidle drivers use the "disabled" field in struct cpuidle_state for quirks which trigger after the initialization of cpuidle, so reading the initial value of that field is not sufficient for those drivers. In order to allow them to implement the quirks without using the "disabled" field in struct cpuidle_state, introduce a new helper function and modify them to use it. Fixes: 99e98d3fb100 ("cpuidle: Consolidate disabled state checks") Reported-by: Len Brown Signed-off-by: Rafael J. Wysocki --- include/linux/cpuidle.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 22602747f468..afb6a573b46d 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -149,6 +149,8 @@ extern int cpuidle_register_driver(struct cpuidle_driver *drv); extern struct cpuidle_driver *cpuidle_get_driver(void); extern struct cpuidle_driver *cpuidle_driver_ref(void); extern void cpuidle_driver_unref(void); +extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx, + bool disable); extern void cpuidle_unregister_driver(struct cpuidle_driver *drv); extern int cpuidle_register_device(struct cpuidle_device *dev); extern void cpuidle_unregister_device(struct cpuidle_device *dev); @@ -186,6 +188,8 @@ static inline int cpuidle_register_driver(struct cpuidle_driver *drv) static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; } static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; } static inline void cpuidle_driver_unref(void) {} +static inline void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, + int idx, bool disable) { } static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { } static inline int cpuidle_register_device(struct cpuidle_device *dev) {return -ENODEV; } -- cgit v1.2.3 From c55b51a06b01d67a99457bb82a8c31081c7faa23 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Sat, 16 Nov 2019 14:16:12 +0100 Subject: cpuidle: Allow idle injection to apply exit latency limit In some cases it may be useful to specify an exit latency limit for the idle state to be used during CPU idle time injection. Instead of duplicating the information in struct cpuidle_device or propagating the latency limit in the call stack, replace the use_deepest_state field with forced_latency_limit_ns to represent that limit, so that the deepest idle state with exit latency within that limit is forced (i.e. no governors) when it is set. A zero exit latency limit for forced idle means to use governors in the usual way (analogous to use_deepest_state equal to "false" before this change). Additionally, add play_idle_precise() taking two arguments, the duration of forced idle and the idle state exit latency limit, both in nanoseconds, and redefine play_idle() as a wrapper around that new function. This change is preparatory, no functional impact is expected. Suggested-by: Rafael J. Wysocki Signed-off-by: Daniel Lezcano [ rjw: Subject, changelog, cpuidle_use_deepest_state() kerneldoc, whitespace ] Signed-off-by: Rafael J. Wysocki --- include/linux/cpu.h | 7 ++++++- include/linux/cpuidle.h | 6 +++--- 2 files changed, 9 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index d0633ebdaa9c..cc03a7848b63 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -179,7 +179,12 @@ 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_precise(u64 duration_ns, u64 latency_ns); + +static inline void play_idle(unsigned long duration_us) +{ + play_idle_precise(duration_us * NSEC_PER_USEC, U64_MAX); +} #ifdef CONFIG_HOTPLUG_CPU bool cpu_wait_death(unsigned int cpu, int seconds); diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index afb6a573b46d..72b26ff1de4b 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -85,7 +85,6 @@ 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; @@ -93,6 +92,7 @@ struct cpuidle_device { int last_state_idx; u64 last_residency_ns; u64 poll_limit_ns; + u64 forced_idle_latency_limit_ns; struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX]; struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX]; struct cpuidle_driver_kobj *kobj_driver; @@ -216,7 +216,7 @@ 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_deepest_state(u64 latency_limit_ns); #else static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev) @@ -224,7 +224,7 @@ 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_deepest_state(u64 latency_limit_ns) { } #endif -- cgit v1.2.3 From 5aa9ba6312e36c18626e73506b92d1513d815435 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Sat, 16 Nov 2019 14:16:13 +0100 Subject: cpuidle: Pass exit latency limit to cpuidle_use_deepest_state() Modify cpuidle_use_deepest_state() to take an additional exit latency limit argument to be passed to find_deepest_idle_state() and make cpuidle_idle_call() pass dev->forced_idle_latency_limit_ns to it for forced idle. Suggested-by: Rafael J. Wysocki Signed-off-by: Daniel Lezcano [ rjw: Rebase and rearrange code, subject & changelog ] Signed-off-by: Rafael J. Wysocki --- include/linux/cpuidle.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 72b26ff1de4b..2dbe46b7c213 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -213,13 +213,15 @@ static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; } #ifdef CONFIG_CPU_IDLE extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, - struct cpuidle_device *dev); + struct cpuidle_device *dev, + u64 latency_limit_ns); extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev); extern void cpuidle_use_deepest_state(u64 latency_limit_ns); #else static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, - struct cpuidle_device *dev) + struct cpuidle_device *dev, + u64 latency_limit_ns) {return -ENODEV; } static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev) -- cgit v1.2.3