To measure time in php you need to use php code.
At the begining run:
$start = time();
and at the end use
$duration = time() - $start;
echo '<script>console.log("Duration ",' . $duration . ');</script>';
You can also echo Start and End but you need to use php time:
echo '<script>console.log("Start ",' . time() . ');</script>';
and
echo '<script>console.log("End ",' . time() . ');</script>';