Commit a4451535 authored by Maria Matejka's avatar Maria Matejka
Browse files

Unified time for whole BIRD 

In previous versions, every thread used its own time structures,
effectively leading to different time in every thread and strange
logging messages.

The time processing code now uses global atomic variables to keep
current time available for fast concurrent reading and safe updates.
parent a2af8073

lib/timer.c

+8 −21
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 


#include "nest/bird.h"



#include "lib/coro.h"

#include "lib/heap.h"

#include "lib/resource.h"

#include "lib/timer.h"
@@ -45,22 +46,10 @@ struct timeloop main_timeloop; 
/* Data accessed and modified from proto/bfd/io.c */

_Thread_local struct timeloop *local_timeloop;



void wakeup_kick_current(void);



btime

current_time(void)

{

  return local_timeloop->last_time;

}

_Atomic btime last_time;

_Atomic btime real_time;



btime

current_real_time(void)

{

  if (!local_timeloop->real_time)

    times_update_real_time(local_timeloop);



  return local_timeloop->real_time;

}

void wakeup_kick_current(void);





#define TIMER_LESS(a,b)		((a)->expires < (b)->expires)
@@ -164,8 +153,6 @@ tm_stop(timer *t) 
void

timers_init(struct timeloop *loop, pool *p)

{

  times_init(loop);



  BUFFER_INIT(loop->timers, p, 4);

  BUFFER_PUSH(loop->timers) = NULL;

}
@@ -178,8 +165,8 @@ timers_fire(struct timeloop *loop) 
  btime base_time;

  timer *t;



  times_update(loop);

  base_time = loop->last_time;

  times_update();

  base_time = current_time();



  while (t = timers_first(loop))

  {
@@ -190,8 +177,8 @@ timers_fire(struct timeloop *loop) 
    {

      btime when = t->expires + t->recurrent;



      if (when <= loop->last_time)

	when = loop->last_time + t->recurrent;

      if (when <= base_time)

	when = base_time + t->recurrent;



      if (t->randomize)

	when += random() % (t->randomize + 1);

lib/timer.h

+7 −7
Original line number Diff line number Diff line
@@ -14,6 +14,10 @@ 
#include "lib/buffer.h"

#include "lib/resource.h"



#include <stdatomic.h>



extern _Atomic btime last_time;

extern _Atomic btime real_time;



typedef struct timer

{
@@ -31,8 +35,6 @@ typedef struct timer 
struct timeloop

{

  BUFFER_(timer *) timers;

  btime last_time;

  btime real_time;

};



static inline uint timers_count(struct timeloop *loop)
@@ -44,8 +46,8 @@ static inline timer *timers_first(struct timeloop *loop) 
extern struct timeloop main_timeloop;

extern _Thread_local struct timeloop *local_timeloop;



btime current_time(void);

btime current_real_time(void);

#define current_time()		atomic_load_explicit(&last_time, memory_order_acquire)

#define current_real_time()	atomic_load_explicit(&real_time, memory_order_acquire)



//#define now (current_time() TO_S)

//#define now_real (current_real_time() TO_S)
@@ -95,9 +97,7 @@ tm_start_max(timer *t, btime after) 
}



/* In sysdep code */

void times_init(struct timeloop *loop);

void times_update(struct timeloop *loop);

void times_update_real_time(struct timeloop *loop);

void times_update(void);



/* For I/O loop */

void timers_init(struct timeloop *loop, pool *p);

proto/bfd/io.c

+4 −4
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ events_init(struct birdloop *loop) 
static void

events_fire(struct birdloop *loop)

{

  times_update(&loop->time);

  times_update();

  ev_run_list(&loop->event_list);

}
@@ -332,7 +332,7 @@ sockets_fire(struct birdloop *loop) 
  sock **psk = loop->poll_sk.data;

  int poll_num = loop->poll_fd.used - 1;



  times_update(&loop->time);

  times_update();



  /* Last fd is internal wakeup fd */

  if (pfd[poll_num].revents & POLLIN)
@@ -461,7 +461,7 @@ birdloop_main(void *arg) 
    events_fire(loop);

    timers_fire(&loop->time);



    times_update(&loop->time);

    times_update();

    if (events_waiting(loop))

      timeout = 0;

    else if (t = timers_first(&loop->time))

sysdep/unix/io.c

+36 −54
Original line number Diff line number Diff line
@@ -123,12 +123,16 @@ rf_fileno(struct rfile *f) 


btime boot_time;





void

times_init(struct timeloop *loop)

times_update(void)

{

  struct timespec ts;

  int rv;



  btime old_time = current_time();

  btime old_real_time = current_real_time();



  rv = clock_gettime(CLOCK_MONOTONIC, &ts);

  if (rv < 0)

    die("Monotonic clock is missing");
@@ -136,42 +140,33 @@ times_init(struct timeloop *loop) 
  if ((ts.tv_sec < 0) || (((u64) ts.tv_sec) > ((u64) 1 << 40)))

    log(L_WARN "Monotonic clock is crazy");

  

  loop->last_time = ts.tv_sec S + ts.tv_nsec NS;

  loop->real_time = 0;

}



void

times_update(struct timeloop *loop)

{

  struct timespec ts;

  int rv;



  rv = clock_gettime(CLOCK_MONOTONIC, &ts);

  if (rv < 0)

    die("clock_gettime: %m");



  btime new_time = ts.tv_sec S + ts.tv_nsec NS;



  if (new_time < loop->last_time)

  if (new_time < old_time)

    log(L_ERR "Monotonic clock is broken");



  loop->last_time = new_time;

  loop->real_time = 0;

}



void

times_update_real_time(struct timeloop *loop)

{

  struct timespec ts;

  int rv;



  rv = clock_gettime(CLOCK_REALTIME, &ts);

  if (rv < 0)

    die("clock_gettime: %m");



  loop->real_time = ts.tv_sec S + ts.tv_nsec NS;

}

  btime new_real_time = ts.tv_sec S + ts.tv_nsec NS;



  if (!atomic_compare_exchange_strong_explicit(

      &last_time,

      &old_time,

      new_time,

      memory_order_acq_rel,

      memory_order_relaxed))

    DBG("Time update collision: last_time");



  if (!atomic_compare_exchange_strong_explicit(

      &real_time,

      &old_real_time,

      new_real_time,

      memory_order_acq_rel,

      memory_order_relaxed))

    DBG("Time update collision: real_time");

}



/**

 * DOC: Sockets
@@ -2017,30 +2012,17 @@ struct event_log_entry 
static struct event_log_entry event_log[EVENT_LOG_LENGTH];

static struct event_log_entry *event_open;

static int event_log_pos, event_log_num, watchdog_active;

static btime last_time;

static btime last_io_time;

static btime loop_time;



static void

io_update_time(void)

{

  struct timespec ts;

  int rv;



  /*

   * This is third time-tracking procedure (after update_times() above and

   * times_update() in BFD), dedicated to internal event log and latency

   * tracking. Hopefully, we consolidate these sometimes.

   */



  rv = clock_gettime(CLOCK_MONOTONIC, &ts);

  if (rv < 0)

    die("clock_gettime: %m");



  last_time = ts.tv_sec S + ts.tv_nsec NS;

  last_io_time = current_time();



  if (event_open)

  {

    event_open->duration = last_time - event_open->timestamp;

    event_open->duration = last_io_time - event_open->timestamp;



    if (event_open->duration > config->latency_limit)

      log(L_WARN "Event 0x%p 0x%p took %d ms",
@@ -2069,7 +2051,7 @@ io_log_event(void *hook, void *data) 


  en->hook = hook;

  en->data = data;

  en->timestamp = last_time;

  en->timestamp = last_io_time;

  en->duration = 0;



  event_log_num++;
@@ -2097,14 +2079,14 @@ io_log_dump(void) 
    struct event_log_entry *en = event_log + (event_log_pos + i) % EVENT_LOG_LENGTH;

    if (en->hook)

      log(L_DEBUG "  Event 0x%p 0x%p at %8d for %d ms", en->hook, en->data,

	  (int) ((last_time - en->timestamp) TO_MS), (int) (en->duration TO_MS));

	  (int) ((last_io_time - en->timestamp) TO_MS), (int) (en->duration TO_MS));

  }

}



void

watchdog_sigalrm(int sig UNUSED)

{

  /* Update last_time and duration, but skip latency check */

  /* Update last_io_time and duration, but skip latency check */

  config->latency_limit = 0xffffffff;

  io_update_time();
@@ -2117,7 +2099,7 @@ watchdog_start1(void) 
{

  io_update_time();



  loop_time = last_time;

  loop_time = last_io_time;

}



static inline void
@@ -2125,7 +2107,7 @@ watchdog_start(void) 
{

  io_update_time();



  loop_time = last_time;

  loop_time = last_io_time;

  event_log_num = 0;



  if (config->watchdog_timeout)
@@ -2146,7 +2128,7 @@ watchdog_stop(void) 
    watchdog_active = 0;

  }



  btime duration = last_time - loop_time;

  btime duration = last_io_time - loop_time;

  if (duration > config->watchdog_warning)

    log(L_WARN "I/O loop cycle took %d ms for %d events",

	(int) (duration TO_MS), event_log_num);
@@ -2202,7 +2184,7 @@ io_loop(void) 
  watchdog_start1();

  for(;;)

    {

      times_update(&main_timeloop);

      times_update();

      events = ev_run_list(&global_event_list);

      events = ev_run_list_limited(&global_work_list, WORK_EVENTS_MAX) || events;

      timers_fire(&main_timeloop);
@@ -2212,7 +2194,7 @@ io_loop(void) 
      poll_tout = (events ? 0 : 3000); /* Time in milliseconds */

      if (t = timers_first(&main_timeloop))

      {

	times_update(&main_timeloop);

	times_update();

	timeout = (tm_remains(t) TO_MS) + 1;

	poll_tout = MIN(poll_tout, timeout);

      }
@@ -2302,7 +2284,7 @@ io_loop(void) 
	    continue;

	  }



	  times_update(&main_timeloop);

	  times_update();



	  /* guaranteed to be non-empty */

	  current_sock = SKIP_BACK(sock, n, HEAD(sock_list));

sysdep/unix/main.c

+1 −0
Original line number Diff line number Diff line
@@ -903,6 +903,7 @@ main(int argc, char **argv) 
    dmalloc_debug(0x2f03d00);

#endif



  times_update();

  resource_sys_init();

  parse_args(argc, argv);

  log_switch(1, NULL, NULL);

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