php - Session expire only on logout -

i working in cakephp project. want keep login session value long user click on logout button. how possible. in advance

the best way set session time out in app/config/core.php.

configure::write('session', array(         'defaults' => 'php',                 'timeout' => 200000,//minutes                 'autoregenerate' => false,//not resets session on activity                 'cookietimeout' => 144000000     ));