phpで処理にかかった時間を取得することはできるのでしょうか？

http://www.webdesignlibrary.jp/2006/08/script_time.html

<?php

// Function to calculate script execution time. 
function microtime_float () 
{ 
list ($msec, $sec) = explode(' ', microtime()); 
$microtime = (float)$msec + (float)$sec; 
return $microtime; 
} 

// Get starting time. 
$start = microtime_float(); 

?> 

Just some text Just some text Just some text 
Just some text Just some text Just some text 
Just some text Just some text Just some text 
Just some text Just some text Just some text 
Just some text Just some text Just some text 

<?php 

$end = microtime_float(); 

// Print results. 
echo 'Script Execution Time: ' . round($end - $start, 3) . ' seconds'; 

?>

↑のようにすると $start = から $end = までの時間が計測できいます。