#ifndef _LINUX_SCHED_CLOCK_H#define _LINUX_SCHED_CLOCK_H #include <linux/smp.h> /* * Do not use outside of architecture code which knows its limitations. * * sched_clock() has no promise of monotonicity or bounded drift between * CPUs, use (which you should not) requires disabling IRQs. * * Please use one of the three interfaces below. */extern unsigned long long notrace sched_clock(void); /* * See the comment in kernel/sched/clock.c */extern u64 running_clock(void);extern u64 sched_clock_cpu(int cpu);  extern void sched_clock_init(void); #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCKstatic inline void sched_clock_init_late(void){} static inline void sched_clock_tick(void){} static inline void clear_sched_clock_stable(void){} static inline void sched_clock_idle_sleep_event(void){} static inline void sched_clock_idle_wakeup_event(u64 delta_ns){} static inline u64 cpu_clock(int cpu){	return sched_clock();} static inline u64 local_clock(void){	return sched_clock();}#elseextern void sched_clock_init_late(void);extern int sched_clock_stable(void);extern void clear_sched_clock_stable(void); /* * When sched_clock_stable(), __sched_clock_offset provides the offset * between local_clock() and sched_clock(). */extern u64 __sched_clock_offset;  extern void sched_clock_tick(void);extern void sched_clock_idle_sleep_event(void);extern void sched_clock_idle_wakeup_event(u64 delta_ns); /* * As outlined in clock.c, provides a fast, high resolution, nanosecond * time source that is monotonic per cpu argument and has bounded drift * between cpus. * * ######################### BIG FAT WARNING ########################## * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can # * # go backwards !!                                                  # * #################################################################### */static inline u64 cpu_clock(int cpu){	return sched_clock_cpu(cpu);} static inline u64 local_clock(void){	return sched_clock_cpu(raw_smp_processor_id());}#endif #ifdef CONFIG_IRQ_TIME_ACCOUNTING/* * An i/f to runtime opt-in for irq time accounting based off of sched_clock. * The reason for this explicit opt-in is not to have perf penalty with * slow sched_clocks. */extern void enable_sched_clock_irqtime(void);extern void disable_sched_clock_irqtime(void);#elsestatic inline void enable_sched_clock_irqtime(void) {}static inline void disable_sched_clock_irqtime(void) {}#endif #endif /* _LINUX_SCHED_CLOCK_H */