usort is bad

usort.php

<?php
$aOpts = getopt('i:');
if (empty($aOpts['i']) === true) {
    $aOpts = array(
       'i' => 10000
    );
}

$aValues = range(0, $aOpts['i'], 1);
shuffle($aValues);
$aTest = array();
foreach ($aValues as $iValue) {
    $aTest[md5($iValue)]['price'] = $iValue;
}


$aClone = $aTest;

$fStart = microtime(true);
usort($aClone, '_usort');
$fUsort = (microtime(true) - $fStart);
print_r('usort: ' . $fUsort . PHP_EOL);

$aClone = $aTest;

$fStart = microtime(true);
_testSort($aClone);
$fTestSort = (microtime(true) - $fStart);
print_r('_testSort: ' . $fTestSort . PHP_EOL);

print_r('Diff: ' . round($fUsort / $fTestSort, 2) . PHP_EOL);

function _usort($a, $b) {
    return $a['price'] > $b['price'] ? 1 : (($a['price'] == $b['price']) ? 0 : -1);
}

function _testSort(&$aSort) {
    $aReturn = $aKeyValue = array();
    foreach ($aSort as $mKey => $aItem) {
        $aKeyValue[$mKey] = $aItem['price'];
    }

    asort($aKeyValue);
    $aKeys = array_keys($aKeyValue);
    foreach ($aKeys as $mKey) {
        $aReturn[] = $aSort[$mKey];
    }

    $aSort = $aReturn;
    unset($aKeys, $aKeyValue, $aReturn);
}