From: Valdis.Kletnieks@vt.edu
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Thomas Bettler <bettlert@student.ethz.ch>,
Matthew Garrett <mgarrett@chiark.greenend.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: cpufreq: shouldn't scaling_min_freq be lower?
Date: Mon, 13 Dec 2004 15:22:46 -0500 [thread overview]
Message-ID: <200412132022.iBDKMkIR031878@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Mon, 06 Dec 2004 13:34:47 GMT." <1102340086.13485.31.camel@localhost.localdomain>
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On Mon, 06 Dec 2004 13:34:47 GMT, Alan Cox said:
> On Sul, 2004-12-05 at 23:29, Thomas Bettler wrote:
> > > Windows tends to use a combination of CPU scaling and throttling to get
> > > the processor that slow. Take a look at
> > > /proc/acpi/processor/*/throttling
> >
> > Is there a throttle daemon for Linux? It would be great to use this.
>
> There are a few. cpuspeed for example
Sorry for the late follow-up. The 'cpuspeed' shipped by Fedora Core as
part of kernel-utils doesn't seem to understand throttling, it only does
frequency stepping. So although I *have*:
[/proc/acpi/processor/CPU0]2 cat power
active state: C2
default state: C1
bus master activity: 00000000
states:
C1: promotion[C2] demotion[--] latency[000] usage[00000010]
*C2: promotion[--] demotion[C1] latency[050] usage[03754116]
C3: <not supported>
[/proc/acpi/processor/CPU0]2 cat throttling
state count: 8
active state: T0
states:
*T0: 00%
T1: 12%
T2: 25%
T3: 37%
T4: 50%
T5: 62%
T6: 75%
T7: 87%
I can basically only tell the CPU to go at 1.2Ghz or 1.6Ghz.
Right now, I use:
cpuspeed -d -p 10 50 -t /proc/acpi/thermal_zone/THM/temperature 85 -a /proc/acpi/ac_adapter/AC/state
which is *almost* OK, thought if further power savings were to be obtained by
dropping it to somewhere in the T5-T7 range if we're at low speed and *still*
not using much CPU, that would be nice (modulo the usual considerations about
latency for T5->T0 transitions for a "Intel(R) Pentium(R) 4 Mobile CPU 1.60GHz"-
I realize other chipsets will have other latencies..)
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prev parent reply other threads:[~2004-12-13 20:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-05 22:06 cpufreq: shouldn't scaling_min_freq be lower? Thomas Bettler
2004-12-05 23:26 ` Matthew Garrett
2004-12-05 23:29 ` Thomas Bettler
2004-12-06 13:34 ` Alan Cox
2004-12-13 20:22 ` Valdis.Kletnieks [this message]
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