Re: [PATCH 1/3]cpuidle take2: Core cpuidle infrastructure

From: Dave Jones
Date: Tue Feb 27 2007 - 11:46:19 EST


On Thu, Feb 22, 2007 at 01:52:57PM -0800, Venkatesh Pallipadi wrote:

> Announcing 'cpuidle', a new CPU power management infrastructure to manage
> idle CPUs in a clean and efficient manner.
> cpuidle separates out the drivers that can provide support for multiple types
> of idle states and policy governors that decide on what idle state to use
> at run time.
> A cpuidle driver can support multiple idle states based on parameters like
> varying power consumption, wakeup latency, etc (ACPI C-states for example).
> A cpuidle governor can be usage model specific (laptop, server,
> laptop on battery etc).
> Main advantage of the infrastructure being, it allows independent development
> of drivers and governors and allows for better CPU power management.

I played with this a little, and got puzzled.
My quad core box used exactly the same amount of power whether the
'ladder' governer was loaded & in use or not. In both situations
it was exactly the same as a vanilla 2.6.20

I'd have expected it to use more until I loaded up 'ladder' to bring it
on par featurewise with 2.6.20. What did I miss?

Dave

--
http://www.codemonkey.org.uk
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