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

[James Bruce <bruce@andrew.cmu.edu>]

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
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