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/*
* Time calculation functions.
*
* Copyright 2000-2011 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <stdint.h>
#include <unistd.h>
#include <sys/time.h>
#include <common/config.h>
#include <common/standard.h>
#include <common/time.h>
#include <common/hathreads.h>
THREAD_LOCAL unsigned int ms_left_scaled; /* milliseconds left for current second (0..2^32-1) */
THREAD_LOCAL unsigned int now_ms; /* internal date in milliseconds (may wrap) */
THREAD_LOCAL unsigned int samp_time; /* total elapsed time over current sample */
THREAD_LOCAL unsigned int idle_time; /* total idle time over current sample */
THREAD_LOCAL unsigned int idle_pct; /* idle to total ratio over last sample (percent) */
THREAD_LOCAL struct timeval now; /* internal date is a monotonic function of real clock */
THREAD_LOCAL struct timeval date; /* the real current date */
struct timeval start_date; /* the process's start date */
THREAD_LOCAL struct timeval before_poll; /* system date before calling poll() */
THREAD_LOCAL struct timeval after_poll; /* system date after leaving poll() */
THREAD_LOCAL uint64_t prev_cpu_time = 0; /* previous per thread CPU time */
THREAD_LOCAL uint64_t prev_mono_time = 0; /* previous system wide monotonic time */
static THREAD_LOCAL struct timeval tv_offset; /* per-thread time ofsset relative to global time */
volatile unsigned long long global_now; /* common date between all threads (32:32) */
/*
* adds <ms> ms to <from>, set the result to <tv> and returns a pointer <tv>
*/
REGPRM3 struct timeval *_tv_ms_add(struct timeval *tv, const struct timeval *from, int ms)
{
tv->tv_usec = from->tv_usec + (ms % 1000) * 1000;
tv->tv_sec = from->tv_sec + (ms / 1000);
while (tv->tv_usec >= 1000000) {
tv->tv_usec -= 1000000;
tv->tv_sec++;
}
return tv;
}
/*
* compares <tv1> and <tv2> modulo 1ms: returns 0 if equal, -1 if tv1 < tv2, 1 if tv1 > tv2
* Must not be used when either argument is eternity. Use tv_ms_cmp2() for that.
*/
REGPRM2 int _tv_ms_cmp(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_ms_cmp(tv1, tv2);
}
/*
* compares <tv1> and <tv2> modulo 1 ms: returns 0 if equal, -1 if tv1 < tv2, 1 if tv1 > tv2,
* assuming that TV_ETERNITY is greater than everything.
*/
REGPRM2 int _tv_ms_cmp2(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_ms_cmp2(tv1, tv2);
}
/*
* compares <tv1> and <tv2> modulo 1 ms: returns 1 if tv1 <= tv2, 0 if tv1 > tv2,
* assuming that TV_ETERNITY is greater than everything. Returns 0 if tv1 is
* TV_ETERNITY, and always assumes that tv2 != TV_ETERNITY. Designed to replace
* occurrences of (tv_ms_cmp2(tv,now) <= 0).
*/
REGPRM2 int _tv_ms_le2(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_ms_le2(tv1, tv2);
}
/*
* returns the remaining time between tv1=now and event=tv2
* if tv2 is passed, 0 is returned.
* Must not be used when either argument is eternity.
*/
REGPRM2 unsigned long _tv_ms_remain(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_ms_remain(tv1, tv2);
}
/*
* returns the remaining time between tv1=now and event=tv2
* if tv2 is passed, 0 is returned.
* Returns TIME_ETERNITY if tv2 is eternity.
*/
REGPRM2 unsigned long _tv_ms_remain2(const struct timeval *tv1, const struct timeval *tv2)
{
if (tv_iseternity(tv2))
return TIME_ETERNITY;
return __tv_ms_remain(tv1, tv2);
}
/*
* Returns the time in ms elapsed between tv1 and tv2, assuming that tv1<=tv2.
* Must not be used when either argument is eternity.
*/
REGPRM2 unsigned long _tv_ms_elapsed(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_ms_elapsed(tv1, tv2);
}
/*
* adds <inc> to <from>, set the result to <tv> and returns a pointer <tv>
*/
REGPRM3 struct timeval *_tv_add(struct timeval *tv, const struct timeval *from, const struct timeval *inc)
{
return __tv_add(tv, from, inc);
}
/*
* If <inc> is set, then add it to <from> and set the result to <tv>, then
* return 1, otherwise return 0. It is meant to be used in if conditions.
*/
REGPRM3 int _tv_add_ifset(struct timeval *tv, const struct timeval *from, const struct timeval *inc)
{
return __tv_add_ifset(tv, from, inc);
}
/*
* Computes the remaining time between tv1=now and event=tv2. if tv2 is passed,
* 0 is returned. The result is stored into tv.
*/
REGPRM3 struct timeval *_tv_remain(const struct timeval *tv1, const struct timeval *tv2, struct timeval *tv)
{
return __tv_remain(tv1, tv2, tv);
}
/*
* Computes the remaining time between tv1=now and event=tv2. if tv2 is passed,
* 0 is returned. The result is stored into tv. Returns ETERNITY if tv2 is
* eternity.
*/
REGPRM3 struct timeval *_tv_remain2(const struct timeval *tv1, const struct timeval *tv2, struct timeval *tv)
{
return __tv_remain2(tv1, tv2, tv);
}
/* tv_isle: compares <tv1> and <tv2> : returns 1 if tv1 <= tv2, otherwise 0 */
REGPRM2 int _tv_isle(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_isle(tv1, tv2);
}
/* tv_isgt: compares <tv1> and <tv2> : returns 1 if tv1 > tv2, otherwise 0 */
REGPRM2 int _tv_isgt(const struct timeval *tv1, const struct timeval *tv2)
{
return __tv_isgt(tv1, tv2);
}
/* tv_update_date: sets <date> to system time, and sets <now> to something as
* close as possible to real time, following a monotonic function. The main
* principle consists in detecting backwards and forwards time jumps and adjust
* an offset to correct them. This function should be called once after each
* poll, and never farther apart than MAX_DELAY_MS*2. The poll's timeout should
* be passed in <max_wait>, and the return value in <interrupted> (a non-zero
* value means that we have not expired the timeout). Calling it with (-1,*)
* sets both <date> and <now> to current date, and calling it with (0,1) simply
* updates the values.
*
* An offset is used to adjust the current time (date), to have a monotonic time
* (now). It must be global and thread-safe. But a timeval cannot be atomically
* updated. So instead, we store it in a 64-bits integer (offset) whose 32 MSB
* contain the signed seconds adjustment andthe 32 LSB contain the unsigned
* microsecond adjustment. We cannot use a timeval for this since it's never
* clearly specified whether a timeval may hold negative values or not.
*/
REGPRM2 void tv_update_date(int max_wait, int interrupted)
{
struct timeval adjusted, deadline, tmp_now, tmp_adj;
unsigned int curr_sec_ms; /* millisecond of current second (0..999) */
unsigned long long old_now;
unsigned long long new_now;
gettimeofday(&date, NULL);
if (unlikely(max_wait < 0)) {
tv_zero(&tv_offset);
adjusted = date;
after_poll = date;
samp_time = idle_time = 0;
idle_pct = 100;
global_now = (((unsigned long long)adjusted.tv_sec) << 32) +
(unsigned int)adjusted.tv_usec;
goto to_ms;
}
__tv_add(&adjusted, &date, &tv_offset);
/* compute the minimum and maximum local date we may have reached based
* on our past date and the associated timeout.
*/
_tv_ms_add(&deadline, &now, max_wait + MAX_DELAY_MS);
if (unlikely(__tv_islt(&adjusted, &now) || __tv_islt(&deadline, &adjusted))) {
/* Large jump. If the poll was interrupted, we consider that the
* date has not changed (immediate wake-up), otherwise we add
* the poll time-out to the previous date. The new offset is
* recomputed.
*/
_tv_ms_add(&adjusted, &now, interrupted ? 0 : max_wait);
}
/* now that we have bounded the local time, let's check if it's
* realistic regarding the global date, which only moves forward,
* otherwise catch up.
*/
old_now = global_now;
do {
tmp_now.tv_sec = (unsigned int)(old_now >> 32);
tmp_now.tv_usec = old_now & 0xFFFFFFFFU;
tmp_adj = adjusted;
if (__tv_islt(&tmp_adj, &tmp_now))
tmp_adj = tmp_now;
/* now <adjusted> is expected to be the most accurate date,
* equal to <global_now> or newer.
*/
new_now = (((unsigned long long)tmp_adj.tv_sec) << 32) + (unsigned int)tmp_adj.tv_usec;
/* let's try to update the global <now> or loop again */
} while (!_HA_ATOMIC_CAS(&global_now, &old_now, new_now));
adjusted = tmp_adj;
/* the new global date when we looked was old_now, and the new one is
* new_now == adjusted. We can recompute our local offset.
*/
tv_offset.tv_sec = adjusted.tv_sec - date.tv_sec;
tv_offset.tv_usec = adjusted.tv_usec - date.tv_usec;
if (tv_offset.tv_usec < 0) {
tv_offset.tv_usec += 1000000;
tv_offset.tv_sec--;
}
to_ms:
now = adjusted;
curr_sec_ms = now.tv_usec / 1000; /* ms of current second */
/* For frequency counters, we'll need to know the ratio of the previous
* value to add to current value depending on the current millisecond.
* The principle is that during the first millisecond, we use 999/1000
* of the past value and that during the last millisecond we use 0/1000
* of the past value. In summary, we only use the past value during the
* first 999 ms of a second, and the last ms is used to complete the
* current measure. The value is scaled to (2^32-1) so that a simple
* multiply followed by a shift gives us the final value.
*/
ms_left_scaled = (999U - curr_sec_ms) * 4294967U;
now_ms = now.tv_sec * 1000 + curr_sec_ms;
return;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/