From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: CPU offline but power consumption increased?
Date: 08 Apr 2007 01:38:14 +0200
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To: Andika Triwidada <andika@gmail.com>
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"Andika Triwidada" <andika@gmail.com> writes:

[cc linux-acpi]
 
> Question: is that normal? I thought power consumption will be
> automatically reduced if one core offlined.

The current cpu offline essentially just runs a special idle loop.
The standard idle loop is even a bit more aggressive on some systems
because it knows about the deeper ACPI sleep modi.

There are also dependencies between cores because current CPUs
have shared power planes between cores.

I suppose in the future when a whole socket goes off line one could
implement special code to turn off the CPU further. But it likely
won't work on older hardware.

-Andi