683be13a28
If nohz is disabled on the kernel command line the [hr]timer code still calls wake_up_nohz_cpu() and tick_nohz_full_cpu(), a pretty pointless exercise. Cache nohz_active in [hr]timer per cpu bases and avoid the overhead. Before: 48.10% hog [.] main 15.25% [kernel] [k] _raw_spin_lock_irqsave 9.76% [kernel] [k] _raw_spin_unlock_irqrestore 6.50% [kernel] [k] mod_timer 6.44% [kernel] [k] lock_timer_base.isra.38 3.87% [kernel] [k] detach_if_pending 3.80% [kernel] [k] del_timer 2.67% [kernel] [k] internal_add_timer 1.33% [kernel] [k] __internal_add_timer 0.73% [kernel] [k] timerfn 0.54% [kernel] [k] wake_up_nohz_cpu After: 48.73% hog [.] main 15.36% [kernel] [k] _raw_spin_lock_irqsave 9.77% [kernel] [k] _raw_spin_unlock_irqrestore 6.61% [kernel] [k] lock_timer_base.isra.38 6.42% [kernel] [k] mod_timer 3.90% [kernel] [k] detach_if_pending 3.76% [kernel] [k] del_timer 2.41% [kernel] [k] internal_add_timer 1.39% [kernel] [k] __internal_add_timer 0.76% [kernel] [k] timerfn We probably should have a cached value for nohz full in the per cpu bases as well to avoid the cpumask check. The base cache line is hot already, the cpumask not necessarily. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Joonwoo Park <joonwoop@codeaurora.org> Cc: Wenbo Wang <wenbo.wang@memblaze.com> Link: http://lkml.kernel.org/r/20150526224512.207378134@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
167 lines
7 KiB
C
167 lines
7 KiB
C
/*
|
|
* tick internal variable and functions used by low/high res code
|
|
*/
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/tick.h>
|
|
|
|
#include "timekeeping.h"
|
|
#include "tick-sched.h"
|
|
|
|
#ifdef CONFIG_GENERIC_CLOCKEVENTS
|
|
|
|
# define TICK_DO_TIMER_NONE -1
|
|
# define TICK_DO_TIMER_BOOT -2
|
|
|
|
DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
|
|
extern ktime_t tick_next_period;
|
|
extern ktime_t tick_period;
|
|
extern int tick_do_timer_cpu __read_mostly;
|
|
|
|
extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
|
|
extern void tick_handle_periodic(struct clock_event_device *dev);
|
|
extern void tick_check_new_device(struct clock_event_device *dev);
|
|
extern void tick_shutdown(unsigned int cpu);
|
|
extern void tick_suspend(void);
|
|
extern void tick_resume(void);
|
|
extern bool tick_check_replacement(struct clock_event_device *curdev,
|
|
struct clock_event_device *newdev);
|
|
extern void tick_install_replacement(struct clock_event_device *dev);
|
|
extern int tick_is_oneshot_available(void);
|
|
extern struct tick_device *tick_get_device(int cpu);
|
|
|
|
extern int clockevents_tick_resume(struct clock_event_device *dev);
|
|
/* Check, if the device is functional or a dummy for broadcast */
|
|
static inline int tick_device_is_functional(struct clock_event_device *dev)
|
|
{
|
|
return !(dev->features & CLOCK_EVT_FEAT_DUMMY);
|
|
}
|
|
|
|
static inline enum clock_event_state clockevent_get_state(struct clock_event_device *dev)
|
|
{
|
|
return dev->state_use_accessors;
|
|
}
|
|
|
|
static inline void clockevent_set_state(struct clock_event_device *dev,
|
|
enum clock_event_state state)
|
|
{
|
|
dev->state_use_accessors = state;
|
|
}
|
|
|
|
extern void clockevents_shutdown(struct clock_event_device *dev);
|
|
extern void clockevents_exchange_device(struct clock_event_device *old,
|
|
struct clock_event_device *new);
|
|
extern void clockevents_switch_state(struct clock_event_device *dev,
|
|
enum clock_event_state state);
|
|
extern int clockevents_program_event(struct clock_event_device *dev,
|
|
ktime_t expires, bool force);
|
|
extern void clockevents_handle_noop(struct clock_event_device *dev);
|
|
extern int __clockevents_update_freq(struct clock_event_device *dev, u32 freq);
|
|
extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
|
|
|
|
/* Broadcasting support */
|
|
# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
|
|
extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu);
|
|
extern void tick_install_broadcast_device(struct clock_event_device *dev);
|
|
extern int tick_is_broadcast_device(struct clock_event_device *dev);
|
|
extern void tick_shutdown_broadcast(unsigned int cpu);
|
|
extern void tick_suspend_broadcast(void);
|
|
extern void tick_resume_broadcast(void);
|
|
extern bool tick_resume_check_broadcast(void);
|
|
extern void tick_broadcast_init(void);
|
|
extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast);
|
|
extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq);
|
|
extern struct tick_device *tick_get_broadcast_device(void);
|
|
extern struct cpumask *tick_get_broadcast_mask(void);
|
|
# else /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST: */
|
|
static inline void tick_install_broadcast_device(struct clock_event_device *dev) { }
|
|
static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; }
|
|
static inline int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { return 0; }
|
|
static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { }
|
|
static inline void tick_shutdown_broadcast(unsigned int cpu) { }
|
|
static inline void tick_suspend_broadcast(void) { }
|
|
static inline void tick_resume_broadcast(void) { }
|
|
static inline bool tick_resume_check_broadcast(void) { return false; }
|
|
static inline void tick_broadcast_init(void) { }
|
|
static inline int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq) { return -ENODEV; }
|
|
|
|
/* Set the periodic handler in non broadcast mode */
|
|
static inline void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
|
|
{
|
|
dev->event_handler = tick_handle_periodic;
|
|
}
|
|
# endif /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST */
|
|
|
|
#else /* !GENERIC_CLOCKEVENTS: */
|
|
static inline void tick_suspend(void) { }
|
|
static inline void tick_resume(void) { }
|
|
#endif /* !GENERIC_CLOCKEVENTS */
|
|
|
|
/* Oneshot related functions */
|
|
#ifdef CONFIG_TICK_ONESHOT
|
|
extern void tick_setup_oneshot(struct clock_event_device *newdev,
|
|
void (*handler)(struct clock_event_device *),
|
|
ktime_t nextevt);
|
|
extern int tick_program_event(ktime_t expires, int force);
|
|
extern void tick_oneshot_notify(void);
|
|
extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
|
|
extern void tick_resume_oneshot(void);
|
|
static inline bool tick_oneshot_possible(void) { return true; }
|
|
extern int tick_oneshot_mode_active(void);
|
|
extern void tick_clock_notify(void);
|
|
extern int tick_check_oneshot_change(int allow_nohz);
|
|
extern int tick_init_highres(void);
|
|
#else /* !CONFIG_TICK_ONESHOT: */
|
|
static inline
|
|
void tick_setup_oneshot(struct clock_event_device *newdev,
|
|
void (*handler)(struct clock_event_device *),
|
|
ktime_t nextevt) { BUG(); }
|
|
static inline void tick_resume_oneshot(void) { BUG(); }
|
|
static inline int tick_program_event(ktime_t expires, int force) { return 0; }
|
|
static inline void tick_oneshot_notify(void) { }
|
|
static inline bool tick_oneshot_possible(void) { return false; }
|
|
static inline int tick_oneshot_mode_active(void) { return 0; }
|
|
static inline void tick_clock_notify(void) { }
|
|
static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
|
|
#endif /* !CONFIG_TICK_ONESHOT */
|
|
|
|
/* Functions related to oneshot broadcasting */
|
|
#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
|
|
extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc);
|
|
extern void tick_broadcast_switch_to_oneshot(void);
|
|
extern void tick_shutdown_broadcast_oneshot(unsigned int cpu);
|
|
extern int tick_broadcast_oneshot_active(void);
|
|
extern void tick_check_oneshot_broadcast_this_cpu(void);
|
|
bool tick_broadcast_oneshot_available(void);
|
|
extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
|
|
#else /* !(BROADCAST && ONESHOT): */
|
|
static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { BUG(); }
|
|
static inline void tick_broadcast_switch_to_oneshot(void) { }
|
|
static inline void tick_shutdown_broadcast_oneshot(unsigned int cpu) { }
|
|
static inline int tick_broadcast_oneshot_active(void) { return 0; }
|
|
static inline void tick_check_oneshot_broadcast_this_cpu(void) { }
|
|
static inline bool tick_broadcast_oneshot_available(void) { return tick_oneshot_possible(); }
|
|
#endif /* !(BROADCAST && ONESHOT) */
|
|
|
|
/* NO_HZ_FULL internal */
|
|
#ifdef CONFIG_NO_HZ_FULL
|
|
extern void tick_nohz_init(void);
|
|
# else
|
|
static inline void tick_nohz_init(void) { }
|
|
#endif
|
|
|
|
#ifdef CONFIG_NO_HZ_COMMON
|
|
extern unsigned long tick_nohz_active;
|
|
#else
|
|
#define tick_nohz_active (0)
|
|
#endif
|
|
|
|
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
|
|
extern void timers_update_migration(bool update_nohz);
|
|
#else
|
|
static inline void timers_update_migration(bool update_nohz) { }
|
|
#endif
|
|
|
|
DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
|
|
|
|
extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
|