Soft-disable CPUs

[Arjan van de Ven]

CC.Fan at gmx.de wrote:
> Currently a Dual-Core CPU is consuming even more power if one core is 
> disabled.
> Is it possible to "soft-disable" a core? So it can idle in C4 and consume very 
> less power.

not on todays kernels; it turns out if you do this you consume MORE 
power (we'll need to investigate and fix that, we should be able to 
just stick it in C4 and never wake it)

> Additionally it would be possible to undervolt this disabled core 
> and thus save more watts.

this isn't possible for two reasons
1) in C4 the cpu already goes to the lowest voltage
2) there is only 1 voltage for the entire cpu package, it's not per core