benchmarker.php

<?php
require 'vendor/autoload.php';
use Symfony\Component\Stopwatch\Stopwatch;

/**
 * @param callable $callable is a function or functor callable with parentheses.
 * @param array ...$args is the argument list which will be supplied to the $callable function.
 * @return float|int which represents the time elapsed in the function called, in milliseconds.
 */
function benchmarker(Callable $callable, ...$args){
    $stopwatch = new Stopwatch(true);
    $stopwatch->start('benchmark');
    $callable(...$args);
    $stopwatch->stop('benchmark');
    $result = $stopwatch->getEvent('benchmark');
    return $result->getDuration();
}

$func = function ($size){
    $arr = array();
    for($i = 0; $i < $size; ++$i){
        $arr[$i] = $i+1;
        echo "Slot $i filled...\n";
    }
};
echo benchmarker($func,10)."ms elapsed.";

A very simple benchmarking function using Symfony's stopwatch to measure the execution time in milliseconds of any single function.