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Member "wrk-4.2.0/src/stats.c" (7 Feb 2021, 2931 Bytes) of package /linux/www/wrk-4.2.0.tar.gz:


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    1 // Copyright (C) 2012 - Will Glozer.  All rights reserved.
    2 
    3 #include <inttypes.h>
    4 #include <stdlib.h>
    5 #include <math.h>
    6 
    7 #include "stats.h"
    8 #include "zmalloc.h"
    9 
   10 stats *stats_alloc(uint64_t max) {
   11     uint64_t limit = max + 1;
   12     stats *s = zcalloc(sizeof(stats) + sizeof(uint64_t) * limit);
   13     s->limit = limit;
   14     s->min   = UINT64_MAX;
   15     return s;
   16 }
   17 
   18 void stats_free(stats *stats) {
   19     zfree(stats);
   20 }
   21 
   22 int stats_record(stats *stats, uint64_t n) {
   23     if (n >= stats->limit) return 0;
   24     __sync_fetch_and_add(&stats->data[n], 1);
   25     __sync_fetch_and_add(&stats->count, 1);
   26     uint64_t min = stats->min;
   27     uint64_t max = stats->max;
   28     while (n < min) min = __sync_val_compare_and_swap(&stats->min, min, n);
   29     while (n > max) max = __sync_val_compare_and_swap(&stats->max, max, n);
   30     return 1;
   31 }
   32 
   33 void stats_correct(stats *stats, int64_t expected) {
   34     for (uint64_t n = expected * 2; n <= stats->max; n++) {
   35         uint64_t count = stats->data[n];
   36         int64_t m = (int64_t) n - expected;
   37         while (count && m > expected) {
   38             stats->data[m] += count;
   39             stats->count += count;
   40             m -= expected;
   41         }
   42     }
   43 }
   44 
   45 long double stats_mean(stats *stats) {
   46     if (stats->count == 0) return 0.0;
   47 
   48     uint64_t sum = 0;
   49     for (uint64_t i = stats->min; i <= stats->max; i++) {
   50         sum += stats->data[i] * i;
   51     }
   52     return sum / (long double) stats->count;
   53 }
   54 
   55 long double stats_stdev(stats *stats, long double mean) {
   56     long double sum = 0.0;
   57     if (stats->count < 2) return 0.0;
   58     for (uint64_t i = stats->min; i <= stats->max; i++) {
   59         if (stats->data[i]) {
   60             sum += powl(i - mean, 2) * stats->data[i];
   61         }
   62     }
   63     return sqrtl(sum / (stats->count - 1));
   64 }
   65 
   66 long double stats_within_stdev(stats *stats, long double mean, long double stdev, uint64_t n) {
   67     long double upper = mean + (stdev * n);
   68     long double lower = mean - (stdev * n);
   69     uint64_t sum = 0;
   70 
   71     for (uint64_t i = stats->min; i <= stats->max; i++) {
   72         if (i >= lower && i <= upper) {
   73             sum += stats->data[i];
   74         }
   75     }
   76 
   77     return (sum / (long double) stats->count) * 100;
   78 }
   79 
   80 uint64_t stats_percentile(stats *stats, long double p) {
   81     uint64_t rank = round((p / 100.0) * stats->count + 0.5);
   82     uint64_t total = 0;
   83     for (uint64_t i = stats->min; i <= stats->max; i++) {
   84         total += stats->data[i];
   85         if (total >= rank) return i;
   86     }
   87     return 0;
   88 }
   89 
   90 uint64_t stats_popcount(stats *stats) {
   91     uint64_t count = 0;
   92     for (uint64_t i = stats->min; i <= stats->max; i++) {
   93         if (stats->data[i]) count++;
   94     }
   95     return count;
   96 }
   97 
   98 uint64_t stats_value_at(stats *stats, uint64_t index, uint64_t *count) {
   99     *count = 0;
  100     for (uint64_t i = stats->min; i <= stats->max; i++) {
  101         if (stats->data[i] && (*count)++ == index) {
  102             *count = stats->data[i];
  103             return i;
  104         }
  105     }
  106     return 0;
  107 }