git.ozlabs.org Git - ccan/blob - ccan/timer/benchmarks/benchmark.c

   1 #include <ccan/time/time.h>
   2 #include <stdint.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 #ifdef FIRST_APPROX
   7 #include "first-approx.c"
   8 #endif
   9 #ifdef SECOND_APPROX
  10 #include "second-approx.c"
  11 #endif
  12 #ifdef NO_APPROX
  13 #include "no-approx.c"
  14 #endif
  15
  16 int main(int argc, char *argv[])
  17 {
  18         struct timespec start, val, val2, end, diff;
  19         unsigned int i, j, limit = atoi(argv[1] ?: "100000");
  20         uint64_t val64;
  21
  22         val = start = time_now();
  23         val64 = to_u64(start);
  24         val2.tv_sec = 0;
  25         val2.tv_nsec = 1;
  26
  27         for (j = 0; j < limit; j++) {
  28                 for (i = 0; i < limit; i++) {
  29                         val = time_add(val, val2);
  30                         val64 += to_u64(val2);
  31                 }
  32         }
  33
  34         end = time_now();
  35
  36         printf("val64 says %lu.%09lu\n",
  37                from_u64(val64).tv_sec,
  38                from_u64(val64).tv_nsec);
  39
  40         printf("val says %lu.%09lu\n",
  41                val.tv_sec,
  42                val.tv_nsec);
  43
  44         if (time_greater(val, from_u64(val64)))
  45                 diff = time_sub(val, from_u64(val64));
  46         else
  47                 diff = time_sub(from_u64(val64), val);
  48
  49         printf("Time %lluns, error = %i%%\n",
  50                (long long)time_to_nsec(time_sub(end, start)),
  51                (int)(100 * time_to_nsec(diff) / time_to_nsec(time_sub(val, start))));
  52         return 0;
  53 }