,   ,   ,   ( 
  ),     ,  -
  .

    loops_per_jiffy     
calibrate_delay(),      init/main.c.

 udelay ()      , -
          -
   .  :     
udelay ()  ,   .   
    mdelay ().       -
 ,   ,   (  mdelay (),
     )  ,   
 .  ,      -
,      ,   
        .  -
    ,      .
           
,     .

 schedule timeout ()

        
schedule_tirneout ().        -
 (sleep)     ,      .
  ,        ,
 ,      .   -
  ,        -
 (wake up)      .   
.

/*        */
set_current_state(TASK_INTERRUPTIBLE) ;

/*      s  */
schedule_timeout(s * HZ) ;

       , -
     .    
    ,    s .
    TASK_INTERRUPTIBLE,     -
    ,     .  
,    ,     TASK_
UNINTERRUPTIBLE.    schedule_timeout ()  
      ,      -
  .

  ,    scheduie_timeout () -
 ,  ,   ,     -
 . ,      

230  10