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From: "Grover, Andrew" <andrew.grover@intel.com>
To: "'Mike Smith'" <msmith@FreeBSD.ORG>,
        Mitsuru IWASAKI
	 <iwasaki@jp.FreeBSD.org>
Cc: acpi-jp@jp.FreeBSD.org
Date: Mon, 9 Jul 2001 17:00:14 -0700 
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Subject: [acpi-jp 1167] RE: HEADS UP - more ACPI updates, CPU throttling 
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X-Originator: andrew.grover@intel.com

> From: Mike Smith [mailto:msmith@FreeBSD.ORG]
> I've committed another round of ACPI changes to -current.
> 
> The major addition is CPU throttling support.  This is 
> implemented using
> ACPI, not any vendor-specific technology, so it should work on any
> platform that exports the relevant information.  By 
> default, the CPU will
> run at 100% in 'performance' mode and 50% in 'economy' 
> mode, however these
> levels can be adjusted with the following sysctls:

Throttling is really something you only want to do when you have to. For
example, to keep the system from overheating.

It is not the best battery/performance tradeoff. Throttling will take less
power, but will also mean that the CPU's work takes twice as long to
complete. You want the processor to be idle, and get it into a low power
state (C1, C2 or C3) as soon as possible.

Regards -- Andy

