Re: Systems running hot?

> Date: Sat, 19 Dec 2009 19:20:19 -0800
> From: Doug Barton <dougb_at_FreeBSD.org>
> Sender: owner-freebsd-current_at_freebsd.org
> 
> Glen Barber wrote:
> > On Sat, Dec 19, 2009 at 9:27 PM, Doug Barton <dougb_at_freebsd.org> wrote:
> >> Paul G Webster wrote:
> >>> tried running powerd on it?
> >> I was not running powerd, but I just enabled it with:
> >> performance_cx_lowest="HIGH"
> >> performance_cpu_freq="HIGH"
> >> economy_cx_lowest="HIGH"
> >> economy_cpu_freq="HIGH"
> >>
> >> If I'm reading the rc.conf man page correctly, that will give me the
> >> benefit of good performance while at the same time dropping the cpu
> >> frequency and power usage when idle?
> >>
> >> Any other suggestions are welcome.
> >>
> > 
> > You can also set settings dependent on the power source:
> > 
> >    powerd_flags="-a max -b adaptive"
> 
> I set it to "-a adaptive -b adaptive" (I'm on AC power most of the
> time) and the good news is that the temp dropped by about 10 degrees C
> and the fan went down to the low speed for the first time today.
> 
> My concern about using this feature is that the last time I used it I
> ended up with problems with my (build into the motherboard) video
> card. I was never sure at the time whether or not the problem with the
> video card was a result of powerd, or of the heat problems I was
> having at the time (back in 8-current when everyone agreed that there
> was a heat problem). I'd like to think that powerd would not fry a
> graphics card, and I don't think that it's even likely, but the system
> is out of warranty now and I can't afford to foul it up.
> 
> The other negative to running powerd is that it causes my display to
> flash occasionally (which of course feeds my "powerd is destroying my
> graphics card" paranoia). It's not life threatening, but it is annoying.
> 
> Thanks to everyone for their suggestions, we'll see how this goes ...
> 
> 
> Doug

powerd has undergone major revision lately (I think in 7.2 and 8.0) to
greatly enhance responsiveness. I have moved to running adaptive at all
times and no longer notice slowness when I kick off some CPU intensive
command. 

Beyond that, read Alexander Motin's power management article at
http://wiki.freebsd.org/TuningPowerConsumption when it's available. (It
seems that the wiki is down at the moment,) Note the comments on
throttling/TCC and deep sleep states. He and I both found TCC and
throttling not worthwhile and possibly causing very unpleasant
side-effects. C (sleep) states are a really big win, but cause problems
on a few systems. 

mav did a great job on this, duplicating my work back in V5 days and
taking it a lot farther than I did. Anyone who wants to save power and
heat really should read it.

I also found the original article at
http://lists.freebsd.org/pipermail/freebsd-current/2009-May/006436.html.
I'm not sure it's identical to the wiki entry, but it is very close and
is currently available.
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