/**
  * @return mixed
  */
 function getClockTick()
 {
     if (self::$clockTick === null) {
         wfSuppressWarnings();
         self::$clockTick = intval(shell_exec('getconf CLK_TCK'));
         wfRestoreWarnings();
         if (!self::$clockTick) {
             self::$clockTick = 100;
         }
     }
     return self::$clockTick;
 }