From owner-freebsd-questions@FreeBSD.ORG  Thu Sep 15 23:52:44 2005
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Date: Fri, 16 Sep 2005 02:52:44 +0300
From: Atis <atissita@btv.lv>
To: freebsd-questions@freebsd.org
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Subject: Re: keeping CPU usage low
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On Thu, 15 Sep 2005 12:11:59 -0400
Charles Swiger <cswiger@mac.com> wrote:

> On Sep 15, 2005, at 11:36 AM, Atis wrote:
> > Is there a way to make the kernel HALT the CPU regularly even
> > when it has got runnable processes? Sort of like increasing the idle
> > thread priority?
> >
> > The problem is with one my computers which has a buggy CPU. No
> > matter how many or how powerful fans I install, when there's
> > a CPU usage of 100% for over ~5 minutes it just overheats
> > and crashes the system.
> 
> If your system hardware supports ACPI power management, you might be  
> able to use the powerd/cpufreq stuff to throttle your CPU to a lower  
> speed.  You might also try underclocking the CPU in your BIOS and/or  
> or set it to a lower clock divider depending on the details of what  
> your hardware supports.
> 

Yes, thank you, the powerd/cpufreq thing does what I need.
I can set the cpu frequency via sysctl.

Well, it's not entirely perfect since on this machine it allows only
two frequencies:

dev.cpu.0.freq_levels: 1739/-1 869/-1

A more software-related solution with the kernel halting
execution would be somewhat cooler, but then again,
I probably don't need it :)


Atis