1 files changed, 93 insertions, 0 deletions
diff --git a/src/php/tests/qps/histogram.php b/src/php/tests/qps/histogram.php
new file mode 100644
index 0000000000..c11a67c618
--- /dev/null
+++ b/src/php/tests/qps/histogram.php
@@ -0,0 +1,93 @@
+<?php
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Histogram class for use in performance testing and measurement
+class Histogram {
+  private $resolution;
+  private $max_possible;
+  private $sum;
+  private $sum_of_squares;
+  private $multiplier;
+  private $count;
+  private $min_seen;
+  private $max_seen;
+  private $buckets;
+
+  private function bucket_for($value) {
+    return (int)(log($value) / log($this->multiplier));
+  }
+
+  public function __construct($resolution, $max_possible) {
+    $this->resolution = $resolution;
+    $this->max_possible = $max_possible;
+    $this->sum = 0;
+    $this->sum_of_squares = 0;
+    $this->multiplier = 1+$resolution;
+    $this->count = 0;
+    $this->min_seen = $max_possible;
+    $this->max_seen = 0;
+    $this->buckets = array_fill(0, $this->bucket_for($max_possible)+1, 0);
+  }
+
+  public function add($value) {
+    $this->sum += $value;
+    $this->sum_of_squares += $value * $value;
+    $this->count += 1;
+    if ($value < $this->min_seen) {
+      $this->min_seen = $value;
+    }
+    if ($value > $this->max_seen) {
+      $this->max_seen = $value;
+    }
+    $this->buckets[$this->bucket_for($value)] += 1;
+  }
+
+  public function minimum() {
+    return $this->min_seen;
+  }
+
+  public function maximum() {
+    return $this->max_seen;
+  }
+
+  public function sum() {
+    return $this->sum;
+  }
+
+  public function sum_of_squares() {
+    return $this->sum_of_squares;
+  }
+
+  public function count() {
+    return $this->count;
+  }
+
+  public function contents() {
+    return $this->buckets;
+  }
+
+  public function clean() {
+    $this->sum = 0;
+    $this->sum_of_squares = 0;
+    $this->count = 0;
+    $this->min_seen = $this->max_possible;
+    $this->max_seen = 0;
+    $this->buckets = array_fill(0, $this->bucket_for($this->max_possible)+1, 0);
+  }
+}