On 2/22/06, Hsieh Steve <stevecfhsieh@xxxxxxxxx> wrote: > Hi ,All > I got some problem about the jiffies in linux2.6.13.2 > in linux 2.6 , jiffies.h is added to <kernel_path>/include/linux for jiffies > definition, > and I found the jiffies is set to -300*HZ as its initial value--> why?? To find issues with jiffies wrapping (it wraps after 5 minutes if it starts at -300*HZ). > furthermore, I found a new varaible jiffies_64 is added, > I see jiffies_u64++ in do_timer() (HW timer ISR), but see NO jiffies++ in > do_timer(), just as the case in linux2.4? > Why? > what relationship between jiffies and jiffies_64? jiffies_64 is a 64-bit quantity. jiffies is a 32-bit quantity which is the lower word of jiffies_64 on 32-bit architectures. Linker magic ensures this correspondence, iirc. In any case, jiffies_64++ therefore has the same result as jiffies++. Please see LDD3 for more details. Thanks, Nish -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
