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comparison third_party/wrk/src/stats.c @ 178:94705b5986b3

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[ThirdParty] Added WRK and luajit for load testing.
author MrJuneJune <me@mrjunejune.com>
date Thu, 22 Jan 2026 20:10:30 -0800
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177:24fe8ff94056 178:94705b5986b3
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 }