lowest C-state changes

[Любомир Григоров]

> Have you checked http://wiki.freebsd.org/TuningPowerConsumption?
I have. It was kind of confusing and didn't know about:
> 1. For CX states to function correctly you better disable throttling
> and powerd. I also witnessed at least one machine that hitting any CX
> mode stops generate interrupts on APIC clock (I had to boot it with a
> mousee until I disabled APIC clocks).
So do you recommend I use throttling or C3? I think C3 runs slightly
cooler. I can't tell since I don't drop under 50C in X. Fan increases at
60C and drops me back.

> 2. You don't need to set each processor CX value, you only need to
> set:
>
> hw.acpi.cpu.cx_lowest=C3
>
> All cpu's will inherit default profile.
>
Thanks.

> First need to see what state the processor supports the current
> system
>sysctl -a | grep cx_
This is before heavy load while it still remembers the C3:

hw.acpi.cpu.cx_lowest: C1
dev.cpu.0.cx_supported: C1/1 C2/80 C3/109
dev.cpu.0.cx_lowest: C3
dev.cpu.0.cx_usage: 0.89% 0.77% 98.32% last 47us
dev.cpu.1.cx_supported: C1/1 C2/80 C3/109
dev.cpu.1.cx_lowest: C3
dev.cpu.1.cx_usage: 3.30% 3.18% 93.50% last 3852us
dev.cpu.2.cx_supported: C1/1 C2/80 C3/109
dev.cpu.2.cx_lowest: C3
dev.cpu.2.cx_usage: 2.95% 1.42% 95.61% last 293us
dev.cpu.3.cx_supported: C1/1 C2/80 C3/109
dev.cpu.3.cx_lowest: C3
dev.cpu.3.cx_usage: 2.73% 1.55% 95.71% last 8471us

After lowest becomes C1, all 4 cores are 100% C1. So I have to manually set
back, or disable powerd or C states. I prefer powerd, tbh, so please
recommend what I should use.

Cheers.

-- 
Lyubomir Grigorov (bgalakazam)