Timer modification

Hi all,
Can any one know how the "timer_adj" calculation is working in
timer.c in linuxkernle2.6.12.5
If we change the HZ value to more than 1000. What hapens to the wall clock.
And i have seen different "time_adj" calculations for HZ 100 and 1000. How to change this calculation for new HZ value. Thanks,
Cjag