Tickless and CPU Idle framework for PPC405

Tickless and CPU Idle framework for PPC405

[seokin Hong]

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Hi, All

 

Is the tickless feature and CPU Idle framework is added in linux tree for
PPC405?


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Re: Tickless and CPU Idle framework for PPC405

[Josh Boyer]

On Thu, Sep 25, 2008 at 06:57:09AM +0900, seokin Hong wrote:
>Hi, All
>
> 
>
>Is the tickless feature and CPU Idle framework is added in linux tree for
>PPC405?

What CPU Idle framework?

josh

RE: Tickless and CPU Idle framework for PPC405

[seokin Hong]

Generic processor idle management framework 
http://ols.108.redhat.com/2007/Reprints/pallipadi-Reprint.pdf

The interface and machine independent interface is in following directory..
/drivers/cpuidle

So, I wonder that the linux kernel ported for PPC405 use this framework to
save power.
And Is the tickless feature is added to that kernel?




-----Original Message-----
From: linuxppc-embedded-bounces+nagne_hsi=naver.com@ozlabs.org
[mailto:linuxppc-embedded-bounces+nagne_hsi=naver.com@ozlabs.org] On Behalf
Of Josh Boyer
Sent: Thursday, September 25, 2008 9:13 AM
To: seokin Hong
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: Tickless and CPU Idle framework for PPC405

On Thu, Sep 25, 2008 at 06:57:09AM +0900, seokin Hong wrote:
>Hi, All
>
> 
>
>Is the tickless feature and CPU Idle framework is added in linux tree for
>PPC405?

What CPU Idle framework?

josh
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Re: Tickless and CPU Idle framework for PPC405

[Josh Boyer]

On Thu, Sep 25, 2008 at 04:17:54PM +0900, seokin Hong wrote:
>Generic processor idle management framework 
>http://ols.108.redhat.com/2007/Reprints/pallipadi-Reprint.pdf
>
>The interface and machine independent interface is in following directory..
>/drivers/cpuidle
>
>So, I wonder that the linux kernel ported for PPC405 use this framework to
>save power.

No.

PPC4xx doesn't have multiple hardware idle states, so having a govenor to
manage that doesn't really make sense.

There was work done to support putting the CPU in wait state on idle for
PowerPC 440 chips.  That could probably be ported over.  Beyond that, the
cpuidle framework just seems like overkill for these CPUs.

>And Is the tickless feature is added to that kernel?

Tickless was added to all of PowerPC around 2.6.21 or 2.6.22 I think.  I
don't recall anything explicitly added for 405, but it should make use of
the generic support.

josh