time.c

   1 #include <time.h>
   2 #include <sys/time.h>
   3
   4 #include "fio.h"
   5
   6 static struct timeval genesis;
   7 static unsigned long ns_granularity;
   8
   9 unsigned long utime_since(struct timeval *s, struct timeval *e)
  10 {
  11         long sec, usec;
  12
  13         sec = e->tv_sec - s->tv_sec;
  14         usec = e->tv_usec - s->tv_usec;
  15         if (sec > 0 && usec < 0) {
  16                 sec--;
  17                 usec += 1000000;
  18         }
  19
  20         sec *= (double) 1000000;
  21
  22         return sec + usec;
  23 }
  24
  25 unsigned long utime_since_now(struct timeval *s)
  26 {
  27         struct timeval t;
  28
  29         fio_gettime(&t, NULL);
  30         return utime_since(s, &t);
  31 }
  32
  33 unsigned long mtime_since(struct timeval *s, struct timeval *e)
  34 {
  35         long sec, usec;
  36
  37         sec = e->tv_sec - s->tv_sec;
  38         usec = e->tv_usec - s->tv_usec;
  39         if (sec > 0 && usec < 0) {
  40                 sec--;
  41                 usec += 1000000;
  42         }
  43
  44         sec *= (double) 1000;
  45         usec /= (double) 1000;
  46
  47         return sec + usec;
  48 }
  49
  50 unsigned long mtime_since_now(struct timeval *s)
  51 {
  52         struct timeval t;
  53         void *p = __builtin_return_address(0);
  54
  55         fio_gettime(&t, p);
  56         return mtime_since(s, &t);
  57 }
  58
  59 unsigned long time_since_now(struct timeval *s)
  60 {
  61         return mtime_since_now(s) / 1000;
  62 }
  63
  64 /*
  65  * busy looping version for the last few usec
  66  */
  67 void __usec_sleep(unsigned int usec)
  68 {
  69         struct timeval start;
  70
  71         fio_gettime(&start, NULL);
  72         while (utime_since_now(&start) < usec)
  73                 nop;
  74 }
  75
  76 void usec_sleep(struct thread_data *td, unsigned long usec)
  77 {
  78         struct timespec req;
  79         struct timeval tv;
  80
  81         do {
  82                 unsigned long ts = usec;
  83
  84                 if (usec < ns_granularity) {
  85                         __usec_sleep(usec);
  86                         break;
  87                 }
  88
  89                 ts = usec - ns_granularity;
  90
  91                 if (ts >= 1000000) {
  92                         req.tv_sec = ts / 1000000;
  93                         ts -= 1000000 * req.tv_sec;
  94                 } else
  95                         req.tv_sec = 0;
  96
  97                 req.tv_nsec = ts * 1000;
  98                 fio_gettime(&tv, NULL);
  99
 100                 if (nanosleep(&req, NULL) < 0)
 101                         break;
 102
 103                 ts = utime_since_now(&tv);
 104                 if (ts >= usec)
 105                         break;
 106
 107                 usec -= ts;
 108         } while (!td->terminate);
 109 }
 110
 111 void rate_throttle(struct thread_data *td, unsigned long time_spent,
 112                    unsigned int bytes)
 113 {
 114         unsigned long usec_cycle;
 115         unsigned int bs;
 116
 117         if (!td->rate)
 118                 return;
 119
 120         if (td_rw(td))
 121                 bs = td->rw_min_bs;
 122         else if (td_read(td))
 123                 bs = td->min_bs[DDIR_READ];
 124         else
 125                 bs = td->min_bs[DDIR_WRITE];
 126
 127         usec_cycle = td->rate_usec_cycle * (bytes / bs);
 128
 129         if (time_spent < usec_cycle) {
 130                 unsigned long s = usec_cycle - time_spent;
 131
 132                 td->rate_pending_usleep += s;
 133                 if (td->rate_pending_usleep >= 100000) {
 134                         usec_sleep(td, td->rate_pending_usleep);
 135                         td->rate_pending_usleep = 0;
 136                 }
 137         } else {
 138                 long overtime = time_spent - usec_cycle;
 139
 140                 td->rate_pending_usleep -= overtime;
 141         }
 142 }
 143
 144 unsigned long mtime_since_genesis(void)
 145 {
 146         return mtime_since_now(&genesis);
 147 }
 148
 149 static void fio_init time_init(void)
 150 {
 151         int i;
 152
 153         /*
 154          * Check the granularity of the nanosleep function
 155          */
 156         for (i = 0; i < 10; i++) {
 157                 struct timeval tv;
 158                 struct timespec ts;
 159                 unsigned long elapsed;
 160
 161                 fio_gettime(&tv, NULL);
 162                 ts.tv_sec = 0;
 163                 ts.tv_nsec = 1000;
 164
 165                 nanosleep(&ts, NULL);
 166                 elapsed = utime_since_now(&tv);
 167
 168                 if (elapsed > ns_granularity)
 169                         ns_granularity = elapsed;
 170         }
 171 }
 172
 173 void set_genesis_time(void)
 174 {
 175         fio_gettime(&genesis, NULL);
 176 }
 177
 178 void fill_start_time(struct timeval *t)
 179 {
 180         memcpy(t, &genesis, sizeof(genesis));
 181 }