Timing script execution at high-precision

gistfile1.php

<?php

$time1 = explode(' ', microtime());
$time1 = $time1[1] . substr($time1[0], 1, -2);

// your code
 
$time2 = explode(' ', microtime());
$time2 = $time2[1] . substr($time2[0], 1, -2);
 
var_dump(bcsub($time2, $time1, 6));