powerd and increase in energy need

[Matthias Gamsjager]

On Wed, Mar 21, 2012 at 1:00 AM, John <john at theusgroup.com> wrote:

> >my zfs nas has an Asus p5e motherboard (x38 chip) and an intel q9300 (quad
> >core 2,5Ghz) processor with all the energy save setting enabled in the
> >bios. Today I connected the power cord to a voltcraft energy meter to see
> >how much energy the whole system needs in idle mode.
> >
> >I found out that with powerd running the cpu get clocked down to 499 mhz
> >with is nice. The funny thing is that this doesn't decrease the amount of
> >watts the machine need. 2,5ghz or 499mhz doen't matter at all. It gets
> even
> >funnier. With powerd running the systems actually needs 4 watts more then
> >without powerd running.
> >
> >Isn't the whole point of powerd to to decease the energy needs of a
> >machine? or is it utterly broken with this cpu generation?
>
> Powerd does decrease energy on my more modern hardware. This machine is
> used
> for backups and is idle much of the time. It runs Freebsd 8.3-Prerelease
> with
> the turbo-boost patch on an i5-650 in an intel DH55HC motherboard.
>
> The following power measurements were made with a Kill-A-Watt meter.
>
> 91w while doing a compile, dev.cpu.0.freq: 3193 (turbo boost enabled)
> 81w compile complete, disks quiet, top reports between 99.9 and 100% idle
>        dev.cpu.0.freq: 3193
> 71w idle for several seconds, powerd running in hiadaptive mode,
>        dev.cpu.0.freq: 1197
>
>
> sysctl dev.cpu |grep cx
> dev.cpu.0.cx_supported: C1/3 C2/205 C3/245
> dev.cpu.0.cx_lowest: C2
> dev.cpu.0.cx_usage: 100.00% 0.00% 0.00% last 259us
>
> sysctl dev.cpu |grep freq                                           ~
> dev.cpu.0.freq: 1197
> dev.cpu.0.freq_levels: 3193/9875 3192/9125 3059/8250 2926/7500 2793/6875
> 2660/6250 2527/5750 2394/5250 2261/4750 1197/2750
>
> /etc/rc.conf
> powerd_flags="-n hadp"
> performance_cx_lowest="C2"
> economy_cx_lowest="C2"
> performance_cpu_freq="HIGH"
>
> John Theus
> TheUs Group
> TheUsGroup.com
>

I will give these setting a try thx..