 ,      jiffies  
 ,   .

(jiffies / HZ)

    . ,   -
      .

unsigned long time stamp = jiffies;    /*  */
unsigned long next_tick = jiffies + 1; /*    

   */
unsigned long later = jiffies + 5*HZ;  /*     

 */

       
,         .

,   j iffies   unsigned long   -
-    .

   jiffies

 jiffies      
unsigned long , ,   32   32- 
  64   64-.   32-  
jiffies      100   , 
      497 ,   -
  .    HZ  1000  -
   47.9 !   64-   jiffies,
       - 
    HZ    .

         -
,          -
    j iffies  unsigned long.   
      .

  ,  jiffies      
 unsigned long.

extern unsigned long volatile jiffies;

     <linux/jiffies.h>  
.

extern u64 jiffies 64;

  ld(l) ,      -
  (   86    arch/i386/kernel/
vmlinux. Ids . S),  ,   jiffies 
    jiffies 64.

Jiffies = jiffies_64;

,  jiffies   32   
64-  jiffies_64.      

214  10