From: Bas Mevissen <ml@basmevissen.nl>
To: Dominik Brodowski <linux@brodo.de>
Cc: cpufreq@www.linux.org.uk
Subject: Re: Which cpufreq driver is best for ...
Date: Thu, 04 Sep 2003 14:36:45 +0200 [thread overview]
Message-ID: <3F5731DD.8050700@basmevissen.nl> (raw)
In-Reply-To: <20030903192749.GA30360@brodo.de>
Dominik Brodowski wrote:
>
> No, speedstep-ich is "superior". p4-clockmod only "throttles" the CPU, i.e.
> it scales down the frequency but not the voltage. This results in an
> approximately linear saving of energy.
I think the confusion about clockmod workings (and hence the savings
that can be gained from it) comes from the fact that "mod" in clockmod
is misinterpreted as "modification" (but it stands for modulation).
> And as long as ACPI C-States "idling" or APM "hlt" instructions work, the
> CPU is "throttled"[*] if there is no work to do anyway, so the p4-clockmod
> driver doesn't save you anything. The p4-clockmod driver almost only is
> useful where ACPI or APM "idling" is borken.
>
Maybe this (together with your extensive explanation in this thread) can
be FAQ-ed. With a good explanation of the power saving models (clock
modulation, clock modification&voltage scaling, cpu idling) a lot of
questions can be answered.
Regards,
Bas.
next prev parent reply other threads:[~2003-09-04 12:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-03 5:57 Which cpufreq driver is best for Norbert Preining
2003-09-03 11:37 ` Bas Mevissen
2003-09-03 14:32 ` Norbert Preining
2003-09-03 15:52 ` Mattia Dongili
2003-09-03 19:30 ` Dominik Brodowski
2003-09-03 19:50 ` Norbert Preining
2003-09-03 21:01 ` Dominik Brodowski
2003-09-04 7:09 ` Norbert Preining
2003-09-04 9:46 ` Dominik Brodowski
2003-09-04 9:59 ` Norbert Preining
2003-09-04 10:04 ` Dominik Brodowski
2003-09-04 9:57 ` Norbert Preining
2003-09-07 19:12 ` Dominik Brodowski
2003-09-04 12:25 ` Bas Mevissen
2003-09-03 19:27 ` Dominik Brodowski
2003-09-04 12:36 ` Bas Mevissen [this message]
2003-09-04 23:27 ` Dominik Brodowski
2003-09-05 8:15 ` Bas Mevissen
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