Dynamic changing of Hz value

[Garcia Jérémie]

Hi everybody,
I'm working on a project that needs the clock granularity changed from 10ms to 5ms while running.
So as a kernel newbie, I understand that I have to deal with the HZ value. I read a lot of things on it through many forums and mailing lists but they always talk about it in a static way (how to fix a value different from 100) as with the Robert love's patch. What I would like to do is to code a routine that allows to modify the HZ value dynamically but the more I read about it and the more I begin to think that it is not possible.
Could someone tell me if, first of all, it is possible? If yes, what would be the process?

Note: I'm using a linux montavista pro 3.1 ( kernel 2.4.20 ) with a powerPC 405EP