       , -
   ,     HZ=USER_HZ.   
 ,         .
,    :     
      ,     -
.

printk("3TO  %lu \", total_time / HZ) ;

   

      ,
    ,    ,   
 ,    .     
      ,      -
      .

  

   (real-time clock, RTC)   -
     .  RTC -
  ,    ,   -
,      .    PC
 RTC   - BIOS.   
      RTC     BIOS.

       RTC   
    ,    
xtime.       ,    -
  ,   86,   
    RTC.   ,   -
        ,  
 xtime.

 

         -
 .    , ,    
 ,          -
,      .  
       ,  -
    .    -
    (decrementer),    -
  ,   ,   ,
  ,       .  -
    ,  .   
     .

   86      -
   (programmable interval timer, PIT).  PIT 

218  10