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 nsec_t;
16 typedef unsigned long long msec_t;
17 typedef unsigned long long usec_t;
18 typedef long long susec_t;
20 typedef usec_t heartbeat_t;
22 /* Linux value is as good as any other */
23 #ifndef CLOCK_REALTIME
24 #define CLOCK_REALTIME 0
27 #ifndef CLOCK_MONOTONIC
28 /* fallback to CLOCK_REALTIME if not available */
29 #define CLOCK_MONOTONIC CLOCK_REALTIME
32 #ifndef CLOCK_BOOTTIME
35 /* CLOCK_BOOTTIME falls back to CLOCK_UPTIME on FreeBSD */
36 #define CLOCK_BOOTTIME CLOCK_UPTIME
38 /* CLOCK_BOOTTIME falls back to CLOCK_MONOTONIC */
39 #define CLOCK_BOOTTIME CLOCK_MONOTONIC
40 #endif // CLOCK_UPTIME
42 #else // CLOCK_BOOTTIME
44 #ifdef HAVE_CLOCK_GETTIME
45 #define CLOCK_BOOTTIME_IS_AVAILABLE 1 // required for /proc/uptime
46 #endif // HAVE_CLOCK_GETTIME
48 #endif // CLOCK_BOOTTIME
50 #define NSEC_PER_MSEC 1000000ULL
52 #define NSEC_PER_SEC 1000000000ULL
53 #define NSEC_PER_USEC 1000ULL
55 #define USEC_PER_SEC 1000000ULL
56 #define MSEC_PER_SEC 1000ULL
58 #ifndef HAVE_CLOCK_GETTIME
59 /* Fallback function for POSIX.1-2001 clock_gettime() function.
61 * We use a realtime clock from gettimeofday(), this will
62 * make systems without clock_gettime() support sensitive
63 * to time jumps or hibernation/suspend side effects.
65 extern int clock_gettime(clockid_t clk_id, struct timespec *ts);
69 * Three clocks are available (cf. man 3 clock_gettime):
71 * REALTIME clock (i.e. wall-clock):
72 * This clock is affected by discontinuous jumps in the system time
73 * (e.g., if the system administrator manually changes the clock), and by the incremental adjustments performed by adjtime(3) and NTP.
76 * Clock that cannot be set and represents monotonic time since some unspecified starting point.
77 * This clock is not affected by discontinuous jumps in the system time
78 * (e.g., if the system administrator manually changes the clock), but is affected by the incremental adjustments performed by adjtime(3) and NTP.
79 * If not available on the system, this clock falls back to REALTIME clock.
82 * Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended.
83 * This allows applications to get a suspend-aware monotonic clock without having to deal with the complications of CLOCK_REALTIME,
84 * which may have discontinuities if the time is changed using settimeofday(2).
85 * If not available on the system, this clock falls back to MONOTONIC clock.
87 * All now_*_timeval() functions fill the `struct timeval` with the time from the appropriate clock.
88 * Those functions return 0 on success, -1 else with errno set appropriately.
90 * All now_*_sec() functions return the time in seconds from the approriate clock, or 0 on error.
91 * All now_*_usec() functions return the time in microseconds from the approriate clock, or 0 on error.
93 extern int now_realtime_timeval(struct timeval *tv);
94 extern time_t now_realtime_sec(void);
95 extern usec_t now_realtime_usec(void);
97 extern int now_monotonic_timeval(struct timeval *tv);
98 extern time_t now_monotonic_sec(void);
99 extern usec_t now_monotonic_usec(void);
101 extern int now_boottime_timeval(struct timeval *tv);
102 extern time_t now_boottime_sec(void);
103 extern usec_t now_boottime_usec(void);
106 extern usec_t timeval_usec(struct timeval *ts);
107 extern msec_t timeval_msec(struct timeval *tv);
109 extern usec_t dt_usec(struct timeval *now, struct timeval *old);
110 extern susec_t dt_usec_signed(struct timeval *now, struct timeval *old);
112 extern void heartbeat_init(heartbeat_t *hb);
114 /* Sleeps until next multiple of tick using monotonic clock.
115 * Returns elapsed time in microseconds since previous heartbeat
117 extern usec_t heartbeat_next(heartbeat_t *hb, usec_t tick);
119 /* Returns elapsed time in microseconds since last heartbeat */
120 extern usec_t heartbeat_dt_usec(heartbeat_t *hb);
122 #endif /* NETDATA_CLOCKS_H */