Re: Power consumption HZ100, HZ250, HZ1000: new numbers

James Bruce
2005-08-02T15:46:25Z

Stephen Clark wrote:
> Maybe new desktop systems - but what about the tens of millions of old
> systems that don't.

If it's an old system, it probably doesn't have working ACPI C-states
though. Without that, low HZ does not save you anything. I should have
said: 99% of desktops with the capability to do ACPI sleep have at least
one USB device attached (usually a mouse).

I do like saving power, which is why I run cpu frequency scaling on
every machine I have that supports it. I'm happy because it does its
savings without negatively impacting latency or high-load performance.
By 2.6.14 dyntick should give us the same thing for HZ, which is why I
think changing the maximum value now doesn't make sense.

- Jim Bruce