include/timers.h

   1 /* This library provides generic watchdog timer management functionality.
   2  * The functions operate on a timer queue provided by the caller. Note that
   3  * the timers must use absolute time to allow sorting. The library provides:
   4  *
   5  *    tmrs_settimer:     (re)set a new watchdog timer in the timers queue
   6  *    tmrs_clrtimer:     remove a timer from both the timers queue
   7  *    tmrs_exptimers:    check for expired timers and run watchdog functions
   8  *
   9  * Author:
  10  *    Jorrit N. Herder <jnherder@cs.vu.nl>
  11  *    Adapted from tmr_settimer and tmr_clrtimer in src/kernel/clock.c.
  12  *    Last modified: September 30, 2004.
  13  */
  14
  15 #ifndef _TIMERS_H
  16 #define _TIMERS_H
  17
  18 #include <limits.h>
  19
  20 #include <sys/types.h>
  21 #include <minix/u64.h>
  22 #include <minix/minlib.h>
  23 #include <minix/endpoint.h>
  24
  25 struct timer;
  26 typedef void (*tmr_func_t)(struct timer *tp);
  27 typedef union { int ta_int; long ta_long; void *ta_ptr; } tmr_arg_t;
  28
  29 /* A timer_t variable must be declare for each distinct timer to be used.
  30  * The timers watchdog function and expiration time are automatically set
  31  * by the library function tmrs_settimer, but its argument is not.
  32  */
  33 typedef struct timer
  34 {
  35   struct timer  *tmr_next;      /* next in a timer chain */
  36   clock_t       tmr_exp_time;   /* expiration time */
  37   tmr_func_t    tmr_func;       /* function to call when expired */
  38   tmr_arg_t     tmr_arg;        /* random argument */
  39 } timer_t;
  40
  41 /* Used when the timer is not active. */
  42 #define TMR_NEVER    ((clock_t) -1 < 0) ? ((clock_t) LONG_MAX) : ((clock_t) -1)
  43 #undef TMR_NEVER
  44 #define TMR_NEVER       ((clock_t) LONG_MAX)
  45
  46 /* These definitions can be used to set or get data from a timer variable. */
  47 #define tmr_arg(tp) (&(tp)->tmr_arg)
  48 #define tmr_exp_time(tp) (&(tp)->tmr_exp_time)
  49
  50 /* Timers should be initialized once before they are being used. Be careful
  51  * not to reinitialize a timer that is in a list of timers, or the chain
  52  * will be broken.
  53  */
  54 #define tmr_inittimer(tp) (void)((tp)->tmr_exp_time = TMR_NEVER, \
  55         (tp)->tmr_next = NULL)
  56
  57 /* The following generic timer management functions are available. They
  58  * can be used to operate on the lists of timers. Adding a timer to a list
  59  * automatically takes care of removing it.
  60  */
  61 clock_t tmrs_clrtimer(timer_t **tmrs, timer_t *tp, clock_t *new_head);
  62 void tmrs_exptimers(timer_t **tmrs, clock_t now, clock_t *new_head);
  63 clock_t tmrs_settimer(timer_t **tmrs, timer_t *tp, clock_t exp_time,
  64         tmr_func_t watchdog, clock_t *new_head);
  65
  66 #define PRINT_STATS(cum_spenttime, cum_instances) {             \
  67                 if(ex64hi(cum_spenttime)) { util_stacktrace(); printf(" ( ??? %lu %lu)\n",      \
  68                         ex64hi(cum_spenttime), ex64lo(cum_spenttime)); } \
  69                 printf("%s:%d,%lu,%lu\n", \
  70                         __FILE__, __LINE__, cum_instances,      \
  71                          ex64lo(cum_spenttime)); \
  72         }
  73
  74 #define RESET_STATS(starttime, cum_instances, cum_spenttime, cum_starttime) { \
  75                 cum_instances = 0;                              \
  76                 cum_starttime = starttime;                      \
  77                 cum_spenttime = make64(0,0);                    \
  78 }
  79
  80 #define TIME_BLOCK_VAR(timed_code_block, time_interval) do {    \
  81         static u64_t _cum_spenttime, _cum_starttime;            \
  82         static int _cum_instances;                              \
  83         u64_t _next_cum_spent, _starttime, _endtime, _dt, _cum_dt;      \
  84         u32_t _dt_micros;                                       \
  85         read_tsc_64(&_starttime);                               \
  86         do { timed_code_block } while(0);                       \
  87         read_tsc_64(&_endtime);                                 \
  88         _dt = sub64(_endtime, _starttime);                      \
  89         if(_cum_instances == 0) {                               \
  90                 RESET_STATS(_starttime, _cum_instances, _cum_spenttime, _cum_starttime); \
  91          }                                                      \
  92         _next_cum_spent = add64(_cum_spenttime, _dt);           \
  93         if(ex64hi(_next_cum_spent)) {                           \
  94                 PRINT_STATS(_cum_spenttime, _cum_instances);    \
  95                 RESET_STATS(_starttime, _cum_instances, _cum_spenttime, _cum_starttime); \
  96         }                                                       \
  97         _cum_spenttime = add64(_cum_spenttime, _dt);            \
  98         _cum_instances++;                                       \
  99         _cum_dt = sub64(_endtime, _cum_starttime);              \
 100         if(cmp64(_cum_dt, make64(0, 120)) > 0) {                \
 101                 PRINT_STATS(_cum_spenttime, _cum_instances);    \
 102                 RESET_STATS(_starttime, _cum_instances, _cum_spenttime, _cum_starttime);        \
 103         }                                                       \
 104 } while(0)
 105
 106 #define TIME_BLOCK(timed_code_block) TIME_BLOCK_VAR(timed_code_block, 100)
 107 #define TIME_BLOCK_T(timed_code_block, t) TIME_BLOCK_VAR(timed_code_block, t)
 108
 109 #endif /* _TIMERS_H */
 110