Re: [patch] i386 dynamic ticks 2.6.13-rc4 (code reordered)

Con Kolivas
2005-08-02T12:04:59Z

On Tue, 2 Aug 2005 21:31, Tony Lindgren wrote:
> * Con Kolivas <kernel@kolivas.org> [050802 03:54]:
>
> > I need to ask you why you think limiting the maximum Hz is a bad idea? On
> > a laptop, say we have set the powersave governor, we have already told
> > the kernel we are interested in maximising power saving at the expense of
> > performance. Would it not be appropriate for this to be linked in a way
> > that sets maximum Hz to some value that maximises power save (whatever
> > that value is) at that time?
>
> With dyntick the system will run at max HZ only when busy. It is possible
> that cutting down max HZ might cause some savings while busy, but I would
> assume the savings are minimal.
>
> I personally prefer to have the performance available when needed, and
> max savings while idle.

That's what I felt too but wasn't sure about the power saving. However what
you say makes complete sense; if the machine is loaded then the extra power
overhead of 1000 vs 100 ticks is meaningless, but throughput may be of
concern. However I managed to get it booted on my p4 at home and while I'm
using it under load I find it rarely gets to 1000Hz during realistic loads.
I'll be posting a fresh patch shortly with the last few cleanups I could
find, that I'm now running on 2.6.13-rc5.

Cheers,
Con