Re: dynamic-hz

Zwane Mwaikambo
2004-12-13T01:50:55Z

On Mon, 13 Dec 2004, Andrea Arcangeli wrote:

> Sure, desktop doesn't need this, the reason somebody is asking for it,
> is that the desktop stuff hurted some other non-desktop usages. Infact
> my 2.4 tree was setting by default HZ=1000 if 'desktop' paramter was
> passed to the kernel (so that I could lower the timeslice accordingly
> too, without losing the effect of the nicelevels between nice 0 and
> +19).
>
> The other new case where I'm asked for this feature is again not the
> desktop but the high end laptop with cpu throttling down to 80mhz, and
> what Pavel mentioned about the lower consumption. Perhaps we could do
> variable HZ there, though I doubt it has a pit that can be reprogrammed
> with sane performance.

Well most x86(64) these days have local APICs and that provides a
relatively inexpensive one shot timer mode.