Re: Power Saving

Phillip Susi
2007-11-27T22:31:43Z

H. Peter Anvin wrote:
> And more importantly, there is no power advantages over T states as
> opposed to C states. They pretty much mean pulsing the system in and
> out of either C1 or C2 depending on the CPU/chipset.

Well, they FORCE the use of the C states to save power, even if the
kernel doesn't want to because it still has runnable tasks. This can be
useful if you know you are running a task that busy waits but would not
suffer from having the performance of the cpu cut in half. Since it is
busy waiting, the kernel never activates the C states, but the
throttling will force it and thus, save you power and heat.