Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_SCHED_CLOCK_H
       3             : #define _LINUX_SCHED_CLOCK_H
       4             : 
       5             : #include <linux/smp.h>
       6             : 
       7             : /*
       8             :  * Do not use outside of architecture code which knows its limitations.
       9             :  *
      10             :  * sched_clock() has no promise of monotonicity or bounded drift between
      11             :  * CPUs, use (which you should not) requires disabling IRQs.
      12             :  *
      13             :  * Please use one of the three interfaces below.
      14             :  */
      15             : extern unsigned long long notrace sched_clock(void);
      16             : 
      17             : /*
      18             :  * See the comment in kernel/sched/clock.c
      19             :  */
      20             : extern u64 running_clock(void);
      21             : extern u64 sched_clock_cpu(int cpu);
      22             : 
      23             : 
      24             : extern void sched_clock_init(void);
      25             : 
      26             : #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
      27             : static inline void sched_clock_tick(void)
      28             : {
      29             : }
      30             : 
      31             : static inline void clear_sched_clock_stable(void)
      32             : {
      33             : }
      34             : 
      35             : static inline void sched_clock_idle_sleep_event(void)
      36             : {
      37             : }
      38             : 
      39             : static inline void sched_clock_idle_wakeup_event(void)
      40             : {
      41             : }
      42             : 
      43             : static inline u64 cpu_clock(int cpu)
      44             : {
      45             :         return sched_clock();
      46             : }
      47             : 
      48             : static inline u64 local_clock(void)
      49             : {
      50             :         return sched_clock();
      51             : }
      52             : #else
      53             : extern int sched_clock_stable(void);
      54             : extern void clear_sched_clock_stable(void);
      55             : 
      56             : /*
      57             :  * When sched_clock_stable(), __sched_clock_offset provides the offset
      58             :  * between local_clock() and sched_clock().
      59             :  */
      60             : extern u64 __sched_clock_offset;
      61             : 
      62             : extern void sched_clock_tick(void);
      63             : extern void sched_clock_tick_stable(void);
      64             : extern void sched_clock_idle_sleep_event(void);
      65             : extern void sched_clock_idle_wakeup_event(void);
      66             : 
      67             : /*
      68             :  * As outlined in clock.c, provides a fast, high resolution, nanosecond
      69             :  * time source that is monotonic per cpu argument and has bounded drift
      70             :  * between cpus.
      71             :  *
      72             :  * ######################### BIG FAT WARNING ##########################
      73             :  * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
      74             :  * # go backwards !!                                                  #
      75             :  * ####################################################################
      76             :  */
      77           0 : static inline u64 cpu_clock(int cpu)
      78             : {
      79           0 :         return sched_clock_cpu(cpu);
      80             : }
      81             : 
      82         308 : static inline u64 local_clock(void)
      83             : {
      84         308 :         return sched_clock_cpu(raw_smp_processor_id());
      85             : }
      86             : #endif
      87             : 
      88             : #ifdef CONFIG_IRQ_TIME_ACCOUNTING
      89             : /*
      90             :  * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
      91             :  * The reason for this explicit opt-in is not to have perf penalty with
      92             :  * slow sched_clocks.
      93             :  */
      94             : extern void enable_sched_clock_irqtime(void);
      95             : extern void disable_sched_clock_irqtime(void);
      96             : #else
      97             : static inline void enable_sched_clock_irqtime(void) {}
      98           0 : static inline void disable_sched_clock_irqtime(void) {}
      99             : #endif
     100             : 
     101             : #endif /* _LINUX_SCHED_CLOCK_H */