PHP/Date/microtime

mixed microtime ( [bool float_output] ) returns a highly accurate reading of the current time

 
<?
echo microtime( );
?>

Timing with microtime()

 
<?php
$start = microtime(true);
for ($i = 0; $i < 1000; $i++) {
    preg_match("/age=\d+/",$_SERVER["QUERY_STRING"]);
}
$end = microtime(true);
$elapsed = $end - $start;