Benchmarking all functions for bottlenecks

Hi, I developed small application in php to make timing of entire collection of drupal functions. May be it yet exists but i've not found anywhere. I've inspired in articles from
http://2bits.com/articles/drupal-performance-tuning-and-optimization-for...

I really need a faster drupal!! It is very very slow (I use D6). I've made this piece of code to help optimizing and find bottlenecks. This code inserts timer_start() and timer_stop() in all functions, in the drupal codebase and in all the installed contributed modules!!
It also removes all the comments // and inserts a timer_stop() before any return statement.

Some functions are leave unmodified, because the algorithm of substitution is very complicated, and it fails the parsing in some conditions (for example, when there are characters {}; inside a string).

Steps for installation are:

1. Make a backup of entire drupal. This script will modify ALL SOURCE CODE, inclusive the contributed modules.
2. Create a setup_timers.php or copy attached file (rename to .php) and place it in drupal base root (same folder as index.php)
3. Run the setup_timers.php ONLY 1 TIME!
4. Modify the index.php file with the code below.
5. Load any page. At end it shows the accumulated time of each function.
6. May be you must repair any generated bug at the source code (nothing is perfect)

I tested it with drupal 6.8.

setup_timers.php:

function replace_returns($m) {
	//print ">> replace_returns<br>";
	//print '<pre>'.var_export($m, true).'</pre>';
	$matches = array();
	$matches2 = array();
	$matches3 = array();
	$r1 = preg_match('/\bpreg/', $m[3], $matches);
	$r2 = preg_match('/\x{22}[^\x{22}]*(\x{2f}\x{2f}|;)[^\x{22}]*\x{22}/', $m[3], $matches2);
	$r3 = preg_match('/\x{27}[^\x{27}]*(\x{2f}\x{2f}|;)[^\x{27}]*\x{27}/', $m[3], $matches3);
	if($r1||$r2||$r3) {
		//print '<pre>'.var_export($matches3, true).'</pre>';
		print "@function $m[1](...) : Possible code breaking, leaving unmodified<br>";
		return $m[0];
	}
	// alternative pattern for comments /\*(?:.|[\r\n])*?\*/
	$new_body = preg_replace('/((?:\/\*(?:[^*]|(?:\*+[^*\/]))*\*+\/)|(?:[^\:]\/\/.*))/', '', $m[3]);
	$new_body = preg_replace('/([^$]\breturn\b[^;]*;)/', '{timer_stop(\''.$m[1].'\'); $1}', $new_body);	
	return "function $m[1]$m[2]{timer_start('$m[1]');$new_body timer_stop('$m[1]');}";
}

function setup_timers_file($filename) {
	if(!filesize($filename))
		return;
	$contents = file_get_contents($filename);
	//print "Changing $filename...<br>";
	//print "Contents: {len=". strlen($contents)."} <pre>".preg_replace('/\<\?php\b/','',$contents) ."</pre><br>";

(THE CODE IS NOT SHOWN CORRECTLY AT NEXT LINE, PLEASE, DOWNLOAD ATTACHED FILE)

	$contents = preg_replace_callback('/***************/', 'replace_returns', $contents);
	file_put_contents($filename, $contents);
	//print "Contents: {len=". strlen($contents)."} <pre>".preg_replace('/\<\?php\b/','',$contents) ."</pre><br>";
	print "Changed $filename<br>";
}

function setup_timers_dir($dir) {
	if(!is_dir($dir))
		return;
	$dir=realpath($dir);
	if ($dh = opendir($dir)) {
		while (($file = readdir($dh)) !== false) {
			//$filename = realpath($dir . "//" . $file);			
			$filename = $dir . "\\" . $file;
			if(filetype($filename) == "dir") {
				if($file!="."&&$file!="..")
					setup_timers_dir($filename);
			}
			else {
				$path_info = pathinfo($filename);				
				if($file!="bootstrap.inc" && in_array($path_info['extension'], array("install", "php", "module", "inc")))
					setup_timers_file($filename);
				else
					print "Jumping " . $filename ."<br>";
			}
		}
		closedir($dh);
	}
}

setup_timers_dir(".");

index.php modified (at end):

...

drupal_page_footer();

function cmp_timers ($a, $b) {
    return ($a['time'] > $b['time']) ? -1 : 1;
}

print "page: ". timer_read("page") . " ms<br>";
uasort($timers, 'cmp_timers');
foreach ($timers as $t => $v) {
	print "$t: " . $v['time'] . " ms<br>";
}

Please, anyone, make me happy, and optimize Drupal!
(first you can optimize or upgrade this code)

Regards