1 #ifndef _LINUX_SCHED_CLOCK_H
2 #define _LINUX_SCHED_CLOCK_H
4 #include <linux/sched.h>
7 * Do not use outside of architecture code which knows its limitations.
9 * sched_clock() has no promise of monotonicity or bounded drift between
10 * CPUs, use (which you should not) requires disabling IRQs.
12 * Please use one of the three interfaces below.
14 extern unsigned long long notrace sched_clock(void);
17 * See the comment in kernel/sched/clock.c
19 extern u64 running_clock(void);
20 extern u64 sched_clock_cpu(int cpu);
23 extern void sched_clock_init(void);
25 #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
26 static inline void sched_clock_init_late(void)
30 static inline void sched_clock_tick(void)
34 static inline void clear_sched_clock_stable(void)
38 static inline void sched_clock_idle_sleep_event(void)
42 static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
46 static inline u64 cpu_clock(int cpu)
51 static inline u64 local_clock(void)
56 extern void sched_clock_init_late(void);
58 * Architectures can set this to 1 if they have specified
59 * CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
60 * but then during bootup it turns out that sched_clock()
61 * is reliable after all:
63 extern int sched_clock_stable(void);
64 extern void clear_sched_clock_stable(void);
66 extern void sched_clock_tick(void);
67 extern void sched_clock_idle_sleep_event(void);
68 extern void sched_clock_idle_wakeup_event(u64 delta_ns);
71 * As outlined in clock.c, provides a fast, high resolution, nanosecond
72 * time source that is monotonic per cpu argument and has bounded drift
75 * ######################### BIG FAT WARNING ##########################
76 * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
78 * ####################################################################
80 static inline u64 cpu_clock(int cpu)
82 return sched_clock_cpu(cpu);
85 static inline u64 local_clock(void)
87 return sched_clock_cpu(raw_smp_processor_id());
91 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
93 * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
94 * The reason for this explicit opt-in is not to have perf penalty with
97 extern void enable_sched_clock_irqtime(void);
98 extern void disable_sched_clock_irqtime(void);
100 static inline void enable_sched_clock_irqtime(void) {}
101 static inline void disable_sched_clock_irqtime(void) {}
104 #endif /* _LINUX_SCHED_CLOCK_H */