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