Benchmarking PHP code block

Benchmarking.php

$n = 1000000;

$time1 = microtime(true);
$mem1  = memory_get_usage(true);

for ($i = 0; $i < $n; $i++)
{

}
                     
$time2 = microtime(true);
$mem2  = memory_get_usage(true);

echo "Test 1: time " . $time2 - $time1 . " - mem " . $mem2 - $mem1;