Re: Context switch times

Davide Libenzi
2001-10-05T22:51:26Z

On Fri, 5 Oct 2001, Alan Cox wrote:

> > Let me see if I have this right. Task priority goes to max on any (?)
> > sleep regardless of how long. And to min if it doesn't sleep for some
> > period of time. Where does the time slice counter come into this, if at
> > all?
> >
> > For what its worth I am currently updating the MontaVista scheduler so,
> > I am open to ideas.
>
> The time slice counter is the limit on the amount of time you can execute,
> the priority determines who runs first.
>
> So if you used your cpu quota you will get run reluctantly. If you slept
> you will get run early and as you use time slice count you will drop
> priority bands, but without pre-emption until you cross a band and there
> is another task with higher priority.
>
> This damps down task thrashing a bit, and for the cpu hogs it gets the
> desired behaviour - which is that the all run their full quantum in the
> background one after another instead of thrashing back and forth

What if we give to prev a priority boost P=F(T) where T is the time
prev is ran before the current schedule ?

- Davide