dump_mem_usage.php

<?php

function max_mem_usage()
{
    $bytes = memory_get_peak_usage();
    $units = array('B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB');
    $mod = 1024;
    $power = $bytes > 0 ? floor(log($bytes, $mod)) : 0;
    return sprintf('%01.2f %s', $bytes / pow($mod, $power), $units[$power]);
}