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Date:      Tue, 18 Nov 2003 22:40:40 -0800 (PST)
From:      Nate Lawson <nate@root.org>
To:        Eric Anderson <anderson@centtech.com>
Cc:        current@freebsd.org
Subject:   Re: acpi_cpu_idle panic (Was: Re: kernel panic with todays source)
Message-ID:  <20031118223605.O66622@root.org>
In-Reply-To: <3FBAF515.6070507@centtech.com>
References:  <20031116120622.O57495@root.org> <200311180346.22259@harrymail> <20031118095752.R64353@root.org> <200311182346.13704@harrymail> <3FBAC2DB.1080004@centtech.com> <20031118172757.S65940@root.org> <3FBAF515.6070507@centtech.com>

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On Tue, 18 Nov 2003, Eric Anderson wrote:
> Nate Lawson wrote:
> >cvsup to -current as of today would be a good first start.  The code was
> >committed Nov 15.  Then boot with acpi enabled and post the output of
> >sysctl hw.acpi.cpu.  You can try different levels by doing sysctl
> >hw.acpi.cpu.cx_lowest=x where x is 0...(number_supported_states - 1)
> >
> Thanks! I've rebuilt and am happy to say that nothing is hosed and I
> booted successfully :)
>
> Here's my sysctl output:
> $ sysctl hw.acpi.cpu
> hw.acpi.cpu.max_speed: 8
> hw.acpi.cpu.current_speed: 4
> hw.acpi.cpu.performance_speed: 8
> hw.acpi.cpu.economy_speed: 4

You should run a benchmark with different values for
hw.acpi.cpu.current_speed to be sure the throttling control still works
ok.  I left it mostly intact so you shouldn't see any problems but it's
still good to test.  As you change it, you should see dmesg output of
"acpi_cpu0: set speed to xx%"

> hw.acpi.cpu.cx_supported: C1/1 C2/1 C3/85 C3/185
> hw.acpi.cpu.cx_lowest: 0
> hw.acpi.cpu.cx_history: 23589/0 0/0 0/0 0/0
>
> I played with the different levels a bit, and can't tell much difference
> in them. Let me know what else I can try to break with this.  Just for
> the info, I booted with a/c plugged in, but did the sysctl running on
> battery.

You should set hw.acpi.cpu.cx_lowest to 1 regularly and 2 or 3 if you're
using battery.  This will save on heat.  I'd also be interested in if
you'd set it to 3 while on battery and run a typical workload for an hour
and then send me the result of sysctl hw.acpi.cpu.  The cx_history value
helps me know if my scheduler is accurate.

> Eric Anderson	   Systems Administrator      Centaur Technology

Say hi to Tom Crispin for me.  :)

-Nate



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