1 files changed, 46 insertions, 0 deletions
diff --git a/dom/serviceworkers/test/performance/perfutils.js b/dom/serviceworkers/test/performance/perfutils.js
new file mode 100644
index 0000000000..d7edbe2fe7
--- /dev/null
+++ b/dom/serviceworkers/test/performance/perfutils.js
@@ -0,0 +1,46 @@
+"use strict";
+
+/**
+ * Given a map from test names to arrays of results, report perfherder metrics
+ * and log full results.
+ */
+function reportMetrics(journal) {
+  let metrics = {};
+  let text = "\nResults (ms)\n";
+
+  const names = Object.keys(journal);
+  const prefixLen = 1 + Math.max(...names.map(str => str.length));
+
+  for (const name in journal) {
+    const med = median(journal[name]);
+    text += (name + ":").padEnd(prefixLen, " ") + stringify(journal[name]);
+    text += "   median " + med + "\n";
+    metrics[name] = med;
+  }
+
+  dump(text);
+  info("perfMetrics", JSON.stringify(metrics));
+}
+
+function median(arr) {
+  arr = [...arr].sort((a, b) => a - b);
+  const mid = Math.floor(arr.length / 2);
+
+  if (arr.length % 2) {
+    return arr[mid];
+  }
+
+  return (arr[mid - 1] + arr[mid]) / 2;
+}
+
+function stringify(arr) {
+  function pad(num) {
+    let s = num.toString().padStart(5, " ");
+    if (s[0] != " ") {
+      s = " " + s;
+    }
+    return s;
+  }
+
+  return arr.reduce((acc, elem) => acc + pad(elem), "");
+}