php session start with save_path

<?php
$dr = $_SERVER['DOCUMENT_ROOT'];
echo '$dr is '.$dr.'<br>';
$dn = dirname($dr);
echo '$dn is '.$dn.'<br>';
$sp = $dn . '/../sessions';
echo '$sp is '.$sp.'<br>';
$rp = realpath($sp);/*C:/sessions on windows*/
echo '$rp is '.$rp.'<br>';
ini_set('session.save_path', $rp);
echo 'ini_get is '.ini_get('session.save_path').'<br>';
session_start();
echo 'session is '.$_SESSION['hello'];
$_SESSION['hello'] = 'boroo';