powerd and multicore

[David Naylor]

Hi,

The way I understand powerd works by default is that it monitors the CPU usage 
(or idleness) and changes the CPU frequency accordingly.  The default values 
are >95% idle => decrease frequency; <65% idle => increase frequency.  

The problem arises when you have a system with 4 or more 'cores'.  In this 
case the first CPU can be running flat out but still report an overall 
idleness of 75% and thus the frequency is not increased even though the first 
core could easily be stuck, at say 200 when capable of 2400.  

Should powerd be changed to look at CPU specific usage and adjust accordingly 
or scale the above defaults according to the number of CPU's.  

Furthermore, currently (with core 2) all CPU's are controlled using a single 
value however (I think) it is possible to have each CPU running on a 
different frequency (and at least with some other architectures).  Does 
powerd handle these cases?

Regards 

David

P.S. sysctl dev.cpu.0.freq=2400 complains about an invalid argument yet 
adjusts the value accordingly.  Is this know or should I file a PR.  

P.P.S. Should the above be filed as a PR?

P.P.P.S. Willing to test patches :-)

P.P.P.P.S. This is the last one :->
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