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Date: Mon, 21 Jan 2008 23:34:41 +0800
From: Erich Dollansky <oceanare@pacific.net.sg>
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To: Andreas Davour <ante@Update.UU.SE>
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Cc: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>,
	freebsd-questions@freebsd.org
Subject: Re: Throttle the CPU when the system is idle
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Hi,

Andreas Davour wrote:
> On Mon, 21 Jan 2008, Wojciech Puchar wrote:
> 
>>>
>>> I have toyed a bit with the dev.cpu.0.freq sysctl setting, and tried 
>>> to lower it automatically when the system load goes down. For some 
>>> reason it don't seem to work, even though the script works for simple 
>>> debug output.
>>>
>>> Anyone have tried to do something similar?
>>
>> no but anyway - freebsd halts CPU when unused, even at full frequency 
>> it uses very little power wne unused.
> 
> Really? Good to know. I was wondering if I could make this laptop of 
> mine a bit cooler, but then I guess not.

I also believe that the CPU is actually halted when idle but using 
powerd brings the temperatures on my machine still down. As powerd can 
be adjusted in which interval it adjusts the CPU frequency, short tasks 
run actually at the minimum frequency if the CPU was idle.

The negative side effect is, that a click takes some time before the 
machine really starts to react if the expected action results in more 
computing.

Erich