diff options
Diffstat (limited to 'libnetdata/clocks')
| -rw-r--r-- | libnetdata/clocks/Makefile.am | 8 | ||||
| -rw-r--r-- | libnetdata/clocks/README.md | 5 | ||||
| -rw-r--r-- | libnetdata/clocks/clocks.c | 300 | ||||
| -rw-r--r-- | libnetdata/clocks/clocks.h | 169 |
4 files changed, 482 insertions, 0 deletions
diff --git a/libnetdata/clocks/Makefile.am b/libnetdata/clocks/Makefile.am new file mode 100644 index 0000000..161784b --- /dev/null +++ b/libnetdata/clocks/Makefile.am @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-3.0-or-later + +AUTOMAKE_OPTIONS = subdir-objects +MAINTAINERCLEANFILES = $(srcdir)/Makefile.in + +dist_noinst_DATA = \ + README.md \ + $(NULL) diff --git a/libnetdata/clocks/README.md b/libnetdata/clocks/README.md new file mode 100644 index 0000000..e53b86a --- /dev/null +++ b/libnetdata/clocks/README.md @@ -0,0 +1,5 @@ +<!-- +custom_edit_url: https://github.com/netdata/netdata/edit/master/libnetdata/clocks/README.md +--> + +[](<>) diff --git a/libnetdata/clocks/clocks.c b/libnetdata/clocks/clocks.c new file mode 100644 index 0000000..4ec5fa9 --- /dev/null +++ b/libnetdata/clocks/clocks.c @@ -0,0 +1,300 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "../libnetdata.h" + +static int clock_boottime_valid = 1; +static int clock_monotonic_coarse_valid = 1; + +#ifndef HAVE_CLOCK_GETTIME +inline int clock_gettime(clockid_t clk_id, struct timespec *ts) { + struct timeval tv; + if(unlikely(gettimeofday(&tv, NULL) == -1)) { + error("gettimeofday() failed."); + return -1; + } + ts->tv_sec = tv.tv_sec; + ts->tv_nsec = (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC; + return 0; +} +#endif + +void test_clock_boottime(void) { + struct timespec ts; + if(clock_gettime(CLOCK_BOOTTIME, &ts) == -1 && errno == EINVAL) + clock_boottime_valid = 0; +} + +void test_clock_monotonic_coarse(void) { + struct timespec ts; + if(clock_gettime(CLOCK_MONOTONIC_COARSE, &ts) == -1 && errno == EINVAL) + clock_monotonic_coarse_valid = 0; +} + +static inline time_t now_sec(clockid_t clk_id) { + struct timespec ts; + if(unlikely(clock_gettime(clk_id, &ts) == -1)) { + error("clock_gettime(%d, ×pec) failed.", clk_id); + return 0; + } + return ts.tv_sec; +} + +static inline usec_t now_usec(clockid_t clk_id) { + struct timespec ts; + if(unlikely(clock_gettime(clk_id, &ts) == -1)) { + error("clock_gettime(%d, ×pec) failed.", clk_id); + return 0; + } + return (usec_t)ts.tv_sec * USEC_PER_SEC + (ts.tv_nsec % NSEC_PER_SEC) / NSEC_PER_USEC; +} + +static inline int now_timeval(clockid_t clk_id, struct timeval *tv) { + struct timespec ts; + + if(unlikely(clock_gettime(clk_id, &ts) == -1)) { + error("clock_gettime(%d, ×pec) failed.", clk_id); + tv->tv_sec = 0; + tv->tv_usec = 0; + return -1; + } + + tv->tv_sec = ts.tv_sec; + tv->tv_usec = (suseconds_t)((ts.tv_nsec % NSEC_PER_SEC) / NSEC_PER_USEC); + return 0; +} + +inline time_t now_realtime_sec(void) { + return now_sec(CLOCK_REALTIME); +} + +inline usec_t now_realtime_usec(void) { + return now_usec(CLOCK_REALTIME); +} + +inline int now_realtime_timeval(struct timeval *tv) { + return now_timeval(CLOCK_REALTIME, tv); +} + +inline time_t now_monotonic_sec(void) { + return now_sec(likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC); +} + +inline usec_t now_monotonic_usec(void) { + return now_usec(likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC); +} + +inline int now_monotonic_timeval(struct timeval *tv) { + return now_timeval(likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC, tv); +} + +inline time_t now_monotonic_high_precision_sec(void) { + return now_sec(CLOCK_MONOTONIC); +} + +inline usec_t now_monotonic_high_precision_usec(void) { + return now_usec(CLOCK_MONOTONIC); +} + +inline int now_monotonic_high_precision_timeval(struct timeval *tv) { + return now_timeval(CLOCK_MONOTONIC, tv); +} + +inline time_t now_boottime_sec(void) { + return now_sec(likely(clock_boottime_valid) ? CLOCK_BOOTTIME : + likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC); +} + +inline usec_t now_boottime_usec(void) { + return now_usec(likely(clock_boottime_valid) ? CLOCK_BOOTTIME : + likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC); +} + +inline int now_boottime_timeval(struct timeval *tv) { + return now_timeval(likely(clock_boottime_valid) ? CLOCK_BOOTTIME : + likely(clock_monotonic_coarse_valid) ? CLOCK_MONOTONIC_COARSE : CLOCK_MONOTONIC, + tv); +} + +inline usec_t timeval_usec(struct timeval *tv) { + return (usec_t)tv->tv_sec * USEC_PER_SEC + (tv->tv_usec % USEC_PER_SEC); +} + +inline msec_t timeval_msec(struct timeval *tv) { + return (msec_t)tv->tv_sec * MSEC_PER_SEC + ((tv->tv_usec % USEC_PER_SEC) / MSEC_PER_SEC); +} + +inline susec_t dt_usec_signed(struct timeval *now, struct timeval *old) { + usec_t ts1 = timeval_usec(now); + usec_t ts2 = timeval_usec(old); + + if(likely(ts1 >= ts2)) return (susec_t)(ts1 - ts2); + return -((susec_t)(ts2 - ts1)); +} + +inline usec_t dt_usec(struct timeval *now, struct timeval *old) { + usec_t ts1 = timeval_usec(now); + usec_t ts2 = timeval_usec(old); + return (ts1 > ts2) ? (ts1 - ts2) : (ts2 - ts1); +} + +inline void heartbeat_init(heartbeat_t *hb) +{ + hb->monotonic = hb->realtime = 0ULL; +} + +// waits for the next heartbeat +// it waits using the monotonic clock +// it returns the dt using the realtime clock + +usec_t heartbeat_next(heartbeat_t *hb, usec_t tick) { + heartbeat_t now; + now.monotonic = now_monotonic_usec(); + now.realtime = now_realtime_usec(); + + usec_t next_monotonic = now.monotonic - (now.monotonic % tick) + tick; + + while(now.monotonic < next_monotonic) { + sleep_usec(next_monotonic - now.monotonic); + now.monotonic = now_monotonic_usec(); + now.realtime = now_realtime_usec(); + } + + if(likely(hb->realtime != 0ULL)) { + usec_t dt_monotonic = now.monotonic - hb->monotonic; + usec_t dt_realtime = now.realtime - hb->realtime; + + hb->monotonic = now.monotonic; + hb->realtime = now.realtime; + + if(unlikely(dt_monotonic >= tick + tick / 2)) { + errno = 0; + error("heartbeat missed %llu monotonic microseconds", dt_monotonic - tick); + } + + return dt_realtime; + } + else { + hb->monotonic = now.monotonic; + hb->realtime = now.realtime; + return 0ULL; + } +} + +// returned the elapsed time, since the last heartbeat +// using the monotonic clock + +inline usec_t heartbeat_monotonic_dt_to_now_usec(heartbeat_t *hb) { + if(!hb || !hb->monotonic) return 0ULL; + return now_monotonic_usec() - hb->monotonic; +} + +int sleep_usec(usec_t usec) { + +#ifndef NETDATA_WITH_USLEEP + // we expect microseconds (1.000.000 per second) + // but timespec is nanoseconds (1.000.000.000 per second) + struct timespec rem, req = { + .tv_sec = (time_t) (usec / 1000000), + .tv_nsec = (suseconds_t) ((usec % 1000000) * 1000) + }; + + while (nanosleep(&req, &rem) == -1) { + if (likely(errno == EINTR)) { + debug(D_SYSTEM, "nanosleep() interrupted (while sleeping for %llu microseconds).", usec); + req.tv_sec = rem.tv_sec; + req.tv_nsec = rem.tv_nsec; + } else { + error("Cannot nanosleep() for %llu microseconds.", usec); + break; + } + } + + return 0; +#else + int ret = usleep(usec); + if(unlikely(ret == -1 && errno == EINVAL)) { + // on certain systems, usec has to be up to 999999 + if(usec > 999999) { + int counter = usec / 999999; + while(counter--) + usleep(999999); + + usleep(usec % 999999); + } + else { + error("Cannot usleep() for %llu microseconds.", usec); + return ret; + } + } + + if(ret != 0) + error("usleep() failed for %llu microseconds.", usec); + + return ret; +#endif +} + +static inline collected_number uptime_from_boottime(void) { +#ifdef CLOCK_BOOTTIME_IS_AVAILABLE + return now_boottime_usec() / 1000; +#else + error("uptime cannot be read from CLOCK_BOOTTIME on this system."); + return 0; +#endif +} + +static procfile *read_proc_uptime_ff = NULL; +static inline collected_number read_proc_uptime(char *filename) { + if(unlikely(!read_proc_uptime_ff)) { + read_proc_uptime_ff = procfile_open(filename, " \t", PROCFILE_FLAG_DEFAULT); + if(unlikely(!read_proc_uptime_ff)) return 0; + } + + read_proc_uptime_ff = procfile_readall(read_proc_uptime_ff); + if(unlikely(!read_proc_uptime_ff)) return 0; + + if(unlikely(procfile_lines(read_proc_uptime_ff) < 1)) { + error("/proc/uptime has no lines."); + return 0; + } + if(unlikely(procfile_linewords(read_proc_uptime_ff, 0) < 1)) { + error("/proc/uptime has less than 1 word in it."); + return 0; + } + + return (collected_number)(strtold(procfile_lineword(read_proc_uptime_ff, 0, 0), NULL) * 1000.0); +} + +inline collected_number uptime_msec(char *filename){ + static int use_boottime = -1; + + if(unlikely(use_boottime == -1)) { + collected_number uptime_boottime = uptime_from_boottime(); + collected_number uptime_proc = read_proc_uptime(filename); + + long long delta = (long long)uptime_boottime - (long long)uptime_proc; + if(delta < 0) delta = -delta; + + if(delta <= 1000 && uptime_boottime != 0) { + procfile_close(read_proc_uptime_ff); + info("Using now_boottime_usec() for uptime (dt is %lld ms)", delta); + use_boottime = 1; + } + else if(uptime_proc != 0) { + info("Using /proc/uptime for uptime (dt is %lld ms)", delta); + use_boottime = 0; + } + else { + error("Cannot find any way to read uptime on this system."); + return 1; + } + } + + collected_number uptime; + if(use_boottime) + uptime = uptime_from_boottime(); + else + uptime = read_proc_uptime(filename); + + return uptime; +} diff --git a/libnetdata/clocks/clocks.h b/libnetdata/clocks/clocks.h new file mode 100644 index 0000000..cfe99f5 --- /dev/null +++ b/libnetdata/clocks/clocks.h @@ -0,0 +1,169 @@ +// 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 + +/* Prefer CLOCK_MONOTONIC_COARSE where available to reduce overhead. It has the same semantics as CLOCK_MONOTONIC */ +#ifndef CLOCK_MONOTONIC_COARSE +/* fallback to CLOCK_MONOTONIC if not available */ +#define CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC +#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_COARSE +#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 + +#ifndef NSEC_PER_MSEC +#define NSEC_PER_MSEC 1000000ULL +#endif + +#ifndef NSEC_PER_SEC +#define NSEC_PER_SEC 1000000000ULL +#endif +#ifndef NSEC_PER_USEC +#define NSEC_PER_USEC 1000ULL +#endif + +#ifndef USEC_PER_SEC +#define USEC_PER_SEC 1000000ULL +#endif +#ifndef MSEC_PER_SEC +#define MSEC_PER_SEC 1000ULL +#endif + +#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. + * + * Most functions will attempt to use CLOCK_MONOTONIC_COARSE if available to reduce contention overhead and improve + * performance scaling. If high precision is required please use one of the available now_*_high_precision_* functions. + */ +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_monotonic_high_precision_timeval(struct timeval *tv); +extern time_t now_monotonic_high_precision_sec(void); +extern usec_t now_monotonic_high_precision_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); + +/* + * When running a binary with CLOCK_BOOTTIME defined on a system with a linux kernel older than Linux 2.6.39 the + * clock_gettime(2) system call fails with EINVAL. In that case it must fall-back to CLOCK_MONOTONIC. + */ +void test_clock_boottime(void); + +/* + * When running a binary with CLOCK_MONOTONIC_COARSE defined on a system with a linux kernel older than Linux 2.6.32 the + * clock_gettime(2) system call fails with EINVAL. In that case it must fall-back to CLOCK_MONOTONIC. + */ +void test_clock_monotonic_coarse(void); + +extern collected_number uptime_msec(char *filename); + +#endif /* NETDATA_CLOCKS_H */ |