strncmp vs strpos, URL routing

<?php

$strpos = function($haystack, $needle, $n) {
	return function() use($haystack, $needle, $n) {
		for($i = 0; $i < $n; $i++) {
			if(0 === strpos($haystack, $needle)) {
				'ok';
			}
		}
	};
};

$strncmp = function($haystack, $needle, $n) {
	$needleLength = strlen($needle);
	return function() use($haystack, $needle, $needleLength, $n) {
		for($i = 0; $i < $n; $i++) {
			if(0 == strncmp($haystack, $needle, $needleLength)) {
				'ok';
			}
		}
	};
};

$bench = function($name, $callback, $n = 3) {
	$result = array();
	echo "Benching $name..." . PHP_EOL;
	for($i = 0; $i < $n; $i++) {
		$start = microtime(true);
		$callback();
		$end = microtime(true);
		$result[$i] = $end - $start;
		echo $i . ': ' . $result[$i] . PHP_EOL;
	}
	return $result;
};


echo '<pre>';

$haystacks = array(
	'short' => '/some/short',
	'long' => '/some/short/haystack/oh-wait-this-is-indeed-a-very-long/and-not-so-short/request-string',
);
$needles = array(
	'short' => '/some',
	'long' => '/some/short',
	'short mismatch' => 'not-found',
	'long mismatch' => 'this-very-long/needle/is-not-found',
);
$n = 1000000;

foreach($haystacks as $hk => $haystack) {
	foreach($needles as $nk => $needle) {
		$strposResult = $bench('strpos ' . $hk . ' ' . $nk, $strpos($haystack, $needle, $n));
		$strncmpResult = $bench('strncmp ' . $hk . ' ' . $nk, $strncmp($haystack, $needle, $n));
		$strposMean = array_sum($strposResult) / count($strposResult);
		$strncmpMean = array_sum($strncmpResult) / count($strncmpResult);
		echo number_format(100 * ($strncmpMean / $strposMean), 2) . '%' . PHP_EOL . PHP_EOL;
	}
}