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Re: CPU power management


On Don, 15 Feb 2007, Eddy Petri??or wrote:

> Eddy Petri??or wrote:
> > Florian Reitmeir wrote:
> sysctl dev.cpu.0.freq_levels
> Results in a list of frequencies down to 31 MHz. I tried some script I
> found on the freebsd lists[1] to test the speed of blowfish at various
> speeds and observed that on my Core 2 Duo that:

i do really doubt this are useful settings, simply because.. 

- to configure a cpu to some voltage and frequency
-> you have to set some bits
- there are limited combinations
- the lowest setting is 0 0 0 0
- the datasheets clearly states what this lowest setting means

more states are possible, but clearly _not_ under the lowest value the cpu is
capable. If your kernel states something like 31 MHz, this is simply an
error caused by some formular which interpolates from some bit settings and
voltage settings the current cpu speed, instead of reading the MSR registers.


Florian Reitmeir

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