memoria usada en un request de php :)

_mem.php

<?php
function _mem($val = null) 
{
    $val = ($val) ? $val : memory_get_peak_usage(true)
    $unit=array('B','KB','MB','GB','TB','PB');
    return @round($val/pow(1024,($i=floor(log($val,1024)))),2).' '.$unit[$i];
}
echo _mem();