latester/histogram.h

   1 #ifndef HISTOGRAM_H
   2 #define HISTOGRAM_H
   3
   4 struct histogram {
   5         unsigned *data;
   6         unsigned allocated;
   7         unsigned resolution;
   8 };
   9
  10 int histogram_init(struct histogram *h,
  11                    unsigned max_value,
  12                    unsigned resolution)
  13 {
  14         size_t mem;
  15         h->allocated = max_value/resolution + 1;
  16         h->resolution = resolution;
  17         mem = h->allocated*sizeof(*h->data);
  18         h->data = malloc(mem);
  19         if (h->data) {
  20                 memset(h->data, 0, mem);
  21                 return 0;
  22         } else
  23                 return -1;
  24 }
  25
  26 void histogram_add(struct histogram *h, int value)
  27 {
  28         if (value < 0) value = 0;
  29         unsigned index = value / h->resolution;
  30         if (index >= h->allocated)
  31                 index = h->allocated - 1;
  32         h->data[index]++;
  33 }
  34
  35 void histogram_fprint(struct histogram *h, FILE *f)
  36 {
  37         unsigned long long sum = 0, cum;
  38         unsigned i;
  39
  40         if (!f)
  41                 return;
  42
  43         for (i = 0; i < h->allocated; i++)
  44                 sum += h->data[i];
  45         cum = sum;
  46         for (i = 0; i < h->allocated; i++) {
  47                 if (h->data[i] != 0) {
  48                         fprintf(f, "%g %lld\n", 1e-3*(i*h->resolution), cum);
  49                 }
  50                 cum -= h->data[i];
  51         }
  52 }
  53
  54
  55 struct histogram_stats {
  56         unsigned count;
  57         unsigned long long sum;
  58         unsigned avg;
  59         unsigned percentile[100];
  60 };
  61
  62 void histogram_stats(struct histogram *h, struct histogram_stats *s)
  63 {
  64         unsigned long long sum;
  65         unsigned i, j;
  66
  67         if (!s)
  68                 return;
  69
  70         memset(s, 0, sizeof(*s));
  71
  72         for (i = 0; i < h->allocated; i++) {
  73                 s->count += h->data[i];
  74                 s->sum += h->data[i] * i * h->resolution;
  75         }
  76         if (s->count == 0)
  77                 return;
  78
  79         s->avg = s->sum / s->count;
  80
  81         for (i = 0, j = 0, sum = 0; i < 100; i++) {
  82                 while (sum <= i * s->count / 100)
  83                         sum += h->data[j++];
  84
  85                 s->percentile[i] = (j-1) * h->resolution;
  86         }
  87         while (sum < i * s->count / 100)
  88                 sum += h->data[j++];
  89         s->percentile[100] = (j-1) * h->resolution;
  90 }
  91
  92 #endif