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Diffstat (limited to 'libnetdata/clocks/clocks.h')
-rw-r--r-- | libnetdata/clocks/clocks.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/libnetdata/clocks/clocks.h b/libnetdata/clocks/clocks.h new file mode 100644 index 0000000..d576d86 --- /dev/null +++ b/libnetdata/clocks/clocks.h @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#ifndef NETDATA_CLOCKS_H +#define NETDATA_CLOCKS_H 1 + +#include "../libnetdata.h" + +#ifndef HAVE_STRUCT_TIMESPEC +struct timespec { + time_t tv_sec; /* seconds */ + long tv_nsec; /* nanoseconds */ +}; +#endif + +#ifndef HAVE_CLOCKID_T +typedef int clockid_t; +#endif + +typedef unsigned long long nsec_t; +typedef unsigned long long msec_t; +typedef unsigned long long usec_t; +typedef long long susec_t; + +typedef struct heartbeat { + usec_t monotonic; + usec_t realtime; +} heartbeat_t; + +/* Linux value is as good as any other */ +#ifndef CLOCK_REALTIME +#define CLOCK_REALTIME 0 +#endif + +#ifndef CLOCK_MONOTONIC +/* fallback to CLOCK_REALTIME if not available */ +#define CLOCK_MONOTONIC CLOCK_REALTIME +#endif + +#ifndef CLOCK_BOOTTIME + +#ifdef CLOCK_UPTIME +/* CLOCK_BOOTTIME falls back to CLOCK_UPTIME on FreeBSD */ +#define CLOCK_BOOTTIME CLOCK_UPTIME +#else // CLOCK_UPTIME +/* CLOCK_BOOTTIME falls back to CLOCK_MONOTONIC */ +#define CLOCK_BOOTTIME CLOCK_MONOTONIC +#endif // CLOCK_UPTIME + +#else // CLOCK_BOOTTIME + +#ifdef HAVE_CLOCK_GETTIME +#define CLOCK_BOOTTIME_IS_AVAILABLE 1 // required for /proc/uptime +#endif // HAVE_CLOCK_GETTIME + +#endif // CLOCK_BOOTTIME + +#define NSEC_PER_MSEC 1000000ULL + +#define NSEC_PER_SEC 1000000000ULL +#define NSEC_PER_USEC 1000ULL + +#define USEC_PER_SEC 1000000ULL +#define MSEC_PER_SEC 1000ULL + +#define USEC_PER_MS 1000ULL + +#ifndef HAVE_CLOCK_GETTIME +/* Fallback function for POSIX.1-2001 clock_gettime() function. + * + * We use a realtime clock from gettimeofday(), this will + * make systems without clock_gettime() support sensitive + * to time jumps or hibernation/suspend side effects. + */ +extern int clock_gettime(clockid_t clk_id, struct timespec *ts); +#endif + +/* + * Three clocks are available (cf. man 3 clock_gettime): + * + * REALTIME clock (i.e. wall-clock): + * This clock is affected by discontinuous jumps in the system time + * (e.g., if the system administrator manually changes the clock), and by the incremental adjustments performed by adjtime(3) and NTP. + * + * MONOTONIC clock + * Clock that cannot be set and represents monotonic time since some unspecified starting point. + * This clock is not affected by discontinuous jumps in the system time + * (e.g., if the system administrator manually changes the clock), but is affected by the incremental adjustments performed by adjtime(3) and NTP. + * If not available on the system, this clock falls back to REALTIME clock. + * + * BOOTTIME clock + * Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended. + * This allows applications to get a suspend-aware monotonic clock without having to deal with the complications of CLOCK_REALTIME, + * which may have discontinuities if the time is changed using settimeofday(2). + * If not available on the system, this clock falls back to MONOTONIC clock. + * + * All now_*_timeval() functions fill the `struct timeval` with the time from the appropriate clock. + * Those functions return 0 on success, -1 else with errno set appropriately. + * + * All now_*_sec() functions return the time in seconds from the approriate clock, or 0 on error. + * All now_*_usec() functions return the time in microseconds from the approriate clock, or 0 on error. + */ +extern int now_realtime_timeval(struct timeval *tv); +extern time_t now_realtime_sec(void); +extern usec_t now_realtime_usec(void); + +extern int now_monotonic_timeval(struct timeval *tv); +extern time_t now_monotonic_sec(void); +extern usec_t now_monotonic_usec(void); + +extern int now_boottime_timeval(struct timeval *tv); +extern time_t now_boottime_sec(void); +extern usec_t now_boottime_usec(void); + + +extern usec_t timeval_usec(struct timeval *tv); +extern msec_t timeval_msec(struct timeval *tv); + +extern usec_t dt_usec(struct timeval *now, struct timeval *old); +extern susec_t dt_usec_signed(struct timeval *now, struct timeval *old); + +extern void heartbeat_init(heartbeat_t *hb); + +/* Sleeps until next multiple of tick using monotonic clock. + * Returns elapsed time in microseconds since previous heartbeat + */ +extern usec_t heartbeat_next(heartbeat_t *hb, usec_t tick); + +/* Returns elapsed time in microseconds since last heartbeat */ +extern usec_t heartbeat_monotonic_dt_to_now_usec(heartbeat_t *hb); + +extern int sleep_usec(usec_t usec); + +#endif /* NETDATA_CLOCKS_H */ |