1 files changed, 73 insertions, 0 deletions
diff --git a/tools/wrk/src/stats.c b/tools/wrk/src/stats.c
new file mode 100644
index 0000000000..a114917bff
--- /dev/null
+++ b/tools/wrk/src/stats.c
@@ -0,0 +1,73 @@
+// Copyright (C) 2012 - Will Glozer.  All rights reserved.
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "stats.h"
+#include "zmalloc.h"
+
+stats *stats_alloc(uint64_t samples) {
+    stats *stats = zcalloc(sizeof(stats) + sizeof(uint64_t) * samples);
+    stats->samples = samples;
+    return stats;
+}
+
+void stats_free(stats *stats) {
+    zfree(stats);
+}
+
+void stats_record(stats *stats, uint64_t x) {
+    stats->data[stats->index++] = x;
+    if (stats->limit < stats->samples)  stats->limit++;
+    if (stats->index == stats->samples) stats->index = 0;
+}
+
+uint64_t stats_min(stats *stats) {
+    uint64_t min = 0;
+    for (uint64_t i = 0; i < stats->limit; i++) {
+        uint64_t x = stats->data[i];
+        if (x < min || min == 0) min = x;
+    }
+    return min;
+}
+
+uint64_t stats_max(stats *stats) {
+    uint64_t max = 0;
+    for (uint64_t i = 0; i < stats->limit; i++) {
+        uint64_t x = stats->data[i];
+        if (x > max || max == 0) max = x;
+    }
+    return max;
+}
+
+long double stats_mean(stats *stats) {
+    uint64_t sum = 0;
+    if (stats->limit == 0) return 0.0;
+    for (uint64_t i = 0; i < stats->limit; i++) {
+        sum += stats->data[i];
+    }
+    return sum / (long double) stats->limit;
+}
+
+long double stats_stdev(stats *stats, long double mean) {
+    long double sum = 0.0;
+    if (stats->limit < 2) return 0.0;
+    for (uint64_t i = 0; i < stats->limit; i++) {
+        sum += powl(stats->data[i] - mean, 2);
+    }
+    return sqrtl(sum / (stats->limit - 1));
+}
+
+long double stats_within_stdev(stats *stats, long double mean, long double stdev, uint64_t n) {
+    long double upper = mean + (stdev * n);
+    long double lower = mean - (stdev * n);
+    uint64_t sum = 0;
+
+    for (uint64_t i = 0; i < stats->limit; i++) {
+        uint64_t x = stats->data[i];
+        if (x >= lower && x <= upper) sum++;
+    }
+
+    return (sum / (long double) stats->limit) * 100;
+}