PHP SessionTimeOut的有关问题

PHP SessionTimeOut的问题
画面在操作的情况下，一样计算时间。给Timeout掉了。为什么？
是哪里设置错误？
下面是PHP.ini的Session配置部分。。。还请各位大虾帮着解决以下。。。


[Session]
;   Handler   used   to   store/retrieve   data.
session.save_handler   =   files

;   Argument   passed   to   save_handler.     In   the   case   of   files,   this   is   the   path
;   where   data   files   are   stored.   Note:   Windows   users   have   to   change   this
;   variable   in   order   to   use   PHP 's   session   functions.
;
;   As   of   PHP   4.0.1,   you   can   define   the   path   as:
;
;           session.save_path   =   "N;/path "
;
;   where   N   is   an   integer.     Instead   of   storing   all   the   session   files   in
;   /path,   what   this   will   do   is   use   subdirectories   N-levels   deep,   and
;   store   the   session   data   in   those   directories.     This   is   useful   if   you
;   or   your   OS   have   problems   with   lots   of   files   in   one   directory,   and   is
;   a   more   efficient   layout   for   servers   that   handle   lots   of   sessions.
;
;   NOTE   1:   PHP   will   not   create   this   directory   structure   automatically.
;                   You   can   use   the   script   in   the   ext/session   dir   for   that   purpose.
;   NOTE   2:   See   the   section   on   garbage   collection   below   if   you   choose   to
;                   use   subdirectories   for   session   storage
;
;   The   file   storage   module   creates   files   using   mode   600   by   default.
;   You   can   change   that   by   using
;
;           session.save_path   =   "N;MODE;/path "
;
;   where   MODE   is   the   octal   representation   of   the   mode.   Note   that   this
;   does   not   overwrite   the   process 's   umask.
;session.save_path   =   "/tmp "

;   Whether   to   use   cookies.
session.use_cookies   =   1

;session.cookie_secure   =  

;   This   option   enables   administrators   to   make   their   users   invulnerable   to
;   attacks   which   involve   passing   session   ids   in   URLs;   defaults   to   0.
;   session.use_only_cookies   =   1

;   Name   of   the   session   (used   as   cookie   name).
session.name   =   sessionName

;   Initialize   session   on   request   startup.
session.auto_start   =   1

;   Lifetime   in   seconds   of   cookie   or,   if   0,   until   browser   is   restarted.