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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 <unistd.h>
#include <sys/time.h>
#include <haproxy/api.h>
#include <haproxy/time.h>
#include <haproxy/ticks.h>
#include <haproxy/tools.h>
struct timeval start_date; /* the process's start date */
struct timeval ready_date; /* date when the process was considered ready */
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 struct timeval now; /* internal date is a monotonic function of real clock */
THREAD_LOCAL struct timeval date; /* the real current date */
THREAD_LOCAL struct timeval before_poll; /* system date before calling poll() */
THREAD_LOCAL struct timeval after_poll; /* system date after leaving poll() */
static unsigned long long now_offset; /* global offset between system time and global time */
volatile unsigned long long global_now; /* common monotonic date between all threads (32:32) */
volatile unsigned int global_now_ms; /* common monotonic date in milliseconds (may wrap) */
static THREAD_LOCAL unsigned int iso_time_sec; /* last iso time value for this thread */
static THREAD_LOCAL char iso_time_str[34]; /* ISO time representation of gettimeofday() */
/*
* adds <ms> ms to <from>, set the result to <tv> and returns a pointer <tv>
*/
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.
*/
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.
*/
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).
*/
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.
*/
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.
*/
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.
*/
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>
*/
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.
*/
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.
*/
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.
*/
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 */
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 */
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).
*
* tv_init_process_date() must have been called once first, and
* tv_init_thread_date() must also have been called once for each thread.
*
* An offset is used to adjust the current time (date), to figure a monotonic
* local time (now). The offset is not critical, as it is only updated after a
* clock jump is detected. From this point all threads will apply it to their
* locally measured time, and will then agree around a common monotonic
* global_now value that serves to further refine their local time. As it is
* not possible to atomically update a timeval, both global_now and the
* now_offset values are instead stored as 64-bit integers made of two 32 bit
* values for the tv_sec and tv_usec parts. The offset is made of two signed
* ints so that the clock can be adjusted in the two directions.
*/
void tv_update_date(int max_wait, int interrupted)
{
struct timeval min_deadline, max_deadline, tmp_now;
unsigned int old_now_ms;
unsigned long long old_now;
unsigned long long new_now;
ullong ofs, ofs_new;
uint sec_ofs, usec_ofs;
gettimeofday(&date, NULL);
/* compute the minimum and maximum local date we may have reached based
* on our past date and the associated timeout. There are three possible
* extremities:
* - the new date cannot be older than before_poll
* - if not interrupted, the new date cannot be older than
* before_poll+max_wait
* - in any case the new date cannot be newer than
* before_poll+max_wait+some margin (100ms used here).
* In case of violation, we'll ignore the current date and instead
* restart from the last date we knew.
*/
_tv_ms_add(&min_deadline, &before_poll, max_wait);
_tv_ms_add(&max_deadline, &before_poll, max_wait + 100);
ofs = HA_ATOMIC_LOAD(&now_offset);
if (unlikely(__tv_islt(&date, &before_poll) || // big jump backwards
(!interrupted && __tv_islt(&date, &min_deadline)) || // small jump backwards
__tv_islt(&max_deadline, &date))) { // big jump forwards
if (!interrupted)
_tv_ms_add(&now, &now, max_wait);
} else {
/* The date is still within expectations. Let's apply the
* now_offset to the system date. Note: ofs if made of two
* independent signed ints.
*/
now.tv_sec = date.tv_sec + (int)(ofs >> 32); // note: may be positive or negative
now.tv_usec = date.tv_usec + (int)ofs; // note: may be positive or negative
if ((int)now.tv_usec < 0) {
now.tv_usec += 1000000;
now.tv_sec -= 1;
} else if (now.tv_usec >= 1000000) {
now.tv_usec -= 1000000;
now.tv_sec += 1;
}
}
/* 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;
old_now_ms = global_now_ms;
do {
tmp_now.tv_sec = (unsigned int)(old_now >> 32);
tmp_now.tv_usec = old_now & 0xFFFFFFFFU;
if (__tv_islt(&now, &tmp_now))
now = tmp_now;
/* now <now> is expected to be the most accurate date,
* equal to <global_now> or newer.
*/
new_now = ((ullong)now.tv_sec << 32) + (uint)now.tv_usec;
now_ms = __tv_to_ms(&now);
/* let's try to update the global <now> (both in timeval
* and ms forms) or loop again.
*/
} while (((new_now != old_now && !_HA_ATOMIC_CAS(&global_now, &old_now, new_now)) ||
(now_ms != old_now_ms && !_HA_ATOMIC_CAS(&global_now_ms, &old_now_ms, now_ms))) &&
__ha_cpu_relax());
/* <now> and <now_ms> are now updated to the last value of global_now
* and global_now_ms, which were also monotonically updated. We can
* compute the latest offset, we don't care who writes it last, the
* variations will not break the monotonic property.
*/
sec_ofs = now.tv_sec - date.tv_sec;
usec_ofs = now.tv_usec - date.tv_usec;
if ((int)usec_ofs < 0) {
usec_ofs += 1000000;
sec_ofs -= 1;
}
ofs_new = ((ullong)sec_ofs << 32) + usec_ofs;
if (ofs_new != ofs)
HA_ATOMIC_STORE(&now_offset, ofs_new);
}
/* must be called once at boot to initialize some global variables */
void tv_init_process_date()
{
now_offset = 0;
gettimeofday(&date, NULL);
now = after_poll = before_poll = date;
global_now = ((ullong)date.tv_sec << 32) + (uint)date.tv_usec;
global_now_ms = now.tv_sec * 1000 + now.tv_usec / 1000;
samp_time = idle_time = 0;
ti->idle_pct = 100;
tv_update_date(0, 1);
}
/* must be called once per thread to initialize their thread-local variables.
* Note that other threads might also be initializing and running in parallel.
*/
void tv_init_thread_date()
{
ullong old_now;
gettimeofday(&date, NULL);
after_poll = before_poll = date;
old_now = _HA_ATOMIC_LOAD(&global_now);
now.tv_sec = old_now >> 32;
now.tv_usec = (uint)old_now;
samp_time = idle_time = 0;
ti->idle_pct = 100;
ti->prev_cpu_time = now_cpu_time();
tv_update_date(0, 1);
}
/* returns the current date as returned by gettimeofday() in ISO+microsecond
* format. It uses a thread-local static variable that the reader can consume
* for as long as it wants until next call. Thus, do not call it from a signal
* handler. If <pad> is non-0, a trailing space will be added. It will always
* return exactly 32 or 33 characters (depending on padding) and will always be
* zero-terminated, thus it will always fit into a 34 bytes buffer.
* This also always include the local timezone (in +/-HH:mm format) .
*/
char *timeofday_as_iso_us(int pad)
{
struct timeval new_date;
struct tm tm;
const char *offset;
char c;
gettimeofday(&new_date, NULL);
if (new_date.tv_sec != iso_time_sec || !new_date.tv_sec) {
get_localtime(new_date.tv_sec, &tm);
offset = get_gmt_offset(new_date.tv_sec, &tm);
if (unlikely(strftime(iso_time_str, sizeof(iso_time_str), "%Y-%m-%dT%H:%M:%S.000000+00:00", &tm) != 32))
strcpy(iso_time_str, "YYYY-mm-ddTHH:MM:SS.000000-00:00"); // make the failure visible but respect format.
iso_time_str[26] = offset[0];
iso_time_str[27] = offset[1];
iso_time_str[28] = offset[2];
iso_time_str[30] = offset[3];
iso_time_str[31] = offset[4];
iso_time_sec = new_date.tv_sec;
}
/* utoa_pad adds a trailing 0 so we save the char for restore */
c = iso_time_str[26];
utoa_pad(new_date.tv_usec, iso_time_str + 20, 7);
iso_time_str[26] = c;
if (pad) {
iso_time_str[32] = ' ';
iso_time_str[33] = 0;
}
return iso_time_str;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/