diff --git a/index.php b/index.php
index 6f011e7e5b..37c157b01f 100644
--- a/index.php
+++ b/index.php
@@ -37,6 +37,8 @@
  * @license  GNU Affero General Public License http://www.gnu.org/licenses/
  */
 
+$_startTime = microtime(true);
+
 define('INSTALLDIR', dirname(__FILE__));
 define('STATUSNET', true);
 define('LACONICA', true); // compatibility
diff --git a/lib/action.php b/lib/action.php
index 0e5d7ae361..24d7527196 100644
--- a/lib/action.php
+++ b/lib/action.php
@@ -111,6 +111,19 @@ class Action extends HTMLOutputter // lawsuit
         }
     }
 
+    function endHTML()
+    {
+        global $_startTime;
+
+        if (isset($_startTime)) {
+            $endTime = microtime(true);
+            $diff = round(($endTime - $_startTime) * 1000);
+            $this->raw("<!-- ${diff}ms -->");
+        }
+
+        return parent::endHTML();
+    }
+
     /**
      * Show head, a template method.
      *