Re: cpufreq doesn't seem to work in Intel Q9300

Dominik Brodowski
2008-08-11T19:33:19Z

Hi,

On Mon, Aug 11, 2008 at 07:11:28AM -0700, Arjan van de Ven wrote:
> 1) when the cpu is idle (as in "idle loop C states/hlt"; p4_clockmod
> doesn't mean anything.. the clock is stopped not just skipped.
> 2) when the cpu is executing code (eg non-idle), it takes more power
> for a unit of time than it takes when it's idle

This statement might be true, but might also be wrong:
a) on systems where only C1 is exported, p4-clockmod most often
equals the state the CPU is in when in C1[*], so we're in a
win-win, or lose-lose situation.
b) IIRC 50% throttling is not "execute-one-statement
skip-one-statement execute-one-statement, etc." but instead
work for N us, skip for N us, work for N us, etc. Therefore,
the situation is a bit more compilcated.

Still, I agree that p4-clockmod is useful mostly in corner cases (and for
developing the cpufreq infrastructure in the first case, but that's another
story)

[*] or C2 even?

Best,
Dominik