1 #ifndef NETDATA_CLOCKS_H
2 #define NETDATA_CLOCKS_H 1
4 #ifndef HAVE_STRUCT_TIMESPEC
6 time_t tv_sec; /* seconds */
7 long tv_nsec; /* nanoseconds */
11 #ifndef HAVE_CLOCKID_T
12 typedef int clockid_t;
15 typedef unsigned long long usec_t;
16 typedef long long susec_t;
18 typedef usec_t heartbeat_t;
20 #ifndef HAVE_CLOCK_GETTIME
21 int clock_gettime(clockid_t clk_id, struct timespec *ts);
24 /* Linux value is as good as any other */
25 #ifndef CLOCK_REALTIME
26 #define CLOCK_REALTIME 0
29 #ifndef CLOCK_MONOTONIC
30 /* fallback to CLOCK_REALTIME if not available */
31 #define CLOCK_MONOTONIC CLOCK_REALTIME
34 #ifndef CLOCK_BOOTTIME
35 /* fallback to CLOCK_MONOTONIC if not available */
36 #define CLOCK_BOOTTIME CLOCK_MONOTONIC
38 #ifdef HAVE_CLOCK_GETTIME
39 #define CLOCK_BOOTTIME_IS_AVAILABLE 1 // required for /proc/uptime
43 #define NSEC_PER_SEC 1000000000ULL
44 #define NSEC_PER_MSEC 1000000ULL
45 #define NSEC_PER_USEC 1000ULL
46 #define USEC_PER_SEC 1000000ULL
48 #ifndef HAVE_CLOCK_GETTIME
49 /* Fallback function for POSIX.1-2001 clock_gettime() function.
51 * We use a realtime clock from gettimeofday(), this will
52 * make systems without clock_gettime() support sensitive
53 * to time jumps or hibernation/suspend side effects.
55 extern int clock_gettime(clockid_t clk_id, struct timespec *ts);
59 * Three clocks are available (cf. man 3 clock_gettime):
61 * REALTIME clock (i.e. wall-clock):
62 * This clock is affected by discontinuous jumps in the system time
63 * (e.g., if the system administrator manually changes the clock), and by the incremental adjustments performed by adjtime(3) and NTP.
66 * Clock that cannot be set and represents monotonic time since some unspecified starting point.
67 * This clock is not affected by discontinuous jumps in the system time
68 * (e.g., if the system administrator manually changes the clock), but is affected by the incremental adjustments performed by adjtime(3) and NTP.
69 * If not available on the system, this clock falls back to REALTIME clock.
72 * Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended.
73 * This allows applications to get a suspend-aware monotonic clock without having to deal with the complications of CLOCK_REALTIME,
74 * which may have discontinuities if the time is changed using settimeofday(2).
75 * If not available on the system, this clock falls back to MONOTONIC clock.
77 * All now_*_timeval() functions fill the `struct timeval` with the time from the appropriate clock.
78 * Those functions return 0 on success, -1 else with errno set appropriately.
80 * All now_*_sec() functions return the time in seconds from the approriate clock, or 0 on error.
81 * All now_*_usec() functions return the time in microseconds from the approriate clock, or 0 on error.
83 extern int now_realtime_timeval(struct timeval *tv);
84 extern time_t now_realtime_sec(void);
85 extern usec_t now_realtime_usec(void);
87 extern int now_monotonic_timeval(struct timeval *tv);
88 extern time_t now_monotonic_sec(void);
89 extern usec_t now_monotonic_usec(void);
91 extern int now_boottime_timeval(struct timeval *tv);
92 extern time_t now_boottime_sec(void);
93 extern usec_t now_boottime_usec(void);
96 extern usec_t timeval_usec(struct timeval *ts);
97 extern usec_t dt_usec(struct timeval *now, struct timeval *old);
98 extern susec_t dt_usec_signed(struct timeval *now, struct timeval *old);
100 extern void heartbeat_init(heartbeat_t *hb);
102 /* Sleeps until next multiple of tick using monotonic clock.
103 * Returns elapsed time in microseconds since previous heartbeat
105 extern usec_t heartbeat_next(heartbeat_t *hb, usec_t tick);
107 /* Returns elapsed time in microseconds since last heartbeat */
108 extern usec_t heartbeat_dt_usec(heartbeat_t *hb);
110 #endif /* NETDATA_CLOCKS_H */