IBM/MontaVista Dynamic Power Management Project

IBM/MontaVista Dynamic Power Management Project

[Bishop Brock]

IBM and MontaVista have initiated a joint project to develop a
dynamic power management control and policy mechanism for Linux
for processors supporting dynamic voltage and frequency scaling.
A paper describing the proposal can be obtained from

http://www.research.ibm.com/arl/projects/dpm.html

A working prototype of the proposed framework for
the IBM PowerPC 405LP processor exists and will be made
public in the near future.

Bishop Brock

IBM Research, Austin Center for Low-Power Computing
11400 Burnet Road    MS/904-6F021
Austin, TX 78758
(512) 838-0149    IBM T/L 678-0149

Re: IBM/MontaVista Dynamic Power Management Project

[Arjan van de Ven]

On Tue, 2002-12-03 at 18:46, Bishop Brock wrote:
> IBM and MontaVista have initiated a joint project to develop a
> dynamic power management control and policy mechanism for Linux
> for processors supporting dynamic voltage and frequency scaling.
> A paper describing the proposal can be obtained from
> 
> http://www.research.ibm.com/arl/projects/dpm.html
> 
> A working prototype of the proposed framework for
> the IBM PowerPC 405LP processor exists and will be made
> public in the near future.

any idea if/how this will fit into the existing cross platform cpufreq
framework ?

Re: [Linux-pm-devel] Re: IBM/MontaVista Dynamic Power Management Project

[Hollis Blanchard]

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On Tue, 2002-12-03 at 11:57, Arjan van de Ven wrote:
> On Tue, 2002-12-03 at 18:46, Bishop Brock wrote:
> > IBM and MontaVista have initiated a joint project to develop a
> > dynamic power management control and policy mechanism for Linux
> > for processors supporting dynamic voltage and frequency scaling.
> > A paper describing the proposal can be obtained from
> > 
> > http://www.research.ibm.com/arl/projects/dpm.html
> > 
> > A working prototype of the proposed framework for
> > the IBM PowerPC 405LP processor exists and will be made
> > public in the near future.
> 
> any idea if/how this will fit into the existing cross platform cpufreq
> framework ?

It subsumes it, similar to Dominik's ideas in "[RFC] Dynamic Frequency
and Voltage Scaling Infrastructure" (on the cpufreq list). The idea is
that you want scaling events to be generated by the kernel rather than
only scaling on userland input. The paper (and Dominik's mail) give you
some ideas of when and why...

-Hollis
-- 
PowerPC Linux
IBM Linux Technology Center

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Re: IBM/MontaVista Dynamic Power Management Project

[Alan Cox]

On Tue, 2002-12-03 at 17:46, Bishop Brock wrote:
> IBM and MontaVista have initiated a joint project to develop a
> dynamic power management control and policy mechanism for Linux
> for processors supporting dynamic voltage and frequency scaling.
> A paper describing the proposal can be obtained from
> 
> http://www.research.ibm.com/arl/projects/dpm.html

Interesting. One small question however. The paper says "Others have
also explored the possibilities of this type of fine grained control".
More to the point however they have patents covering them. What does IBM
intend to do about that ?

Re: [Linux-pm-devel] IBM/MontaVista Dynamic Power Management Project

[Hollis Blanchard]

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Please note that the cpufreq list address was incorrect in the original
mail; please cc cpufreq@www.linux.org.uk (not .uk.org :) on future
replies.

-Hollis
-- 
PowerPC Linux
IBM Linux Technology Center

On Tue, 2002-12-03 at 11:46, Bishop Brock wrote:
> IBM and MontaVista have initiated a joint project to develop a
> dynamic power management control and policy mechanism for Linux
> for processors supporting dynamic voltage and frequency scaling.
> A paper describing the proposal can be obtained from
> 
> http://www.research.ibm.com/arl/projects/dpm.html
> 
> A working prototype of the proposed framework for
> the IBM PowerPC 405LP processor exists and will be made
> public in the near future.
> 
> Bishop Brock
> 
> IBM Research, Austin Center for Low-Power Computing
> 11400 Burnet Road    MS/904-6F021
> Austin, TX 78758
> (512) 838-0149    IBM T/L 678-0149
> 
> 
> 
> 
> 
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> 


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Re: [Linux-pm-devel] Re: IBM/MontaVista Dynamic Power Management Project

[Dominik Brodowski]

On Tue, Dec 03, 2002 at 12:27:03PM -0600, Hollis Blanchard wrote:
> On Tue, 2002-12-03 at 11:57, Arjan van de Ven wrote:
> > On Tue, 2002-12-03 at 18:46, Bishop Brock wrote:
> > > IBM and MontaVista have initiated a joint project to develop a
> > > dynamic power management control and policy mechanism for Linux
> > > for processors supporting dynamic voltage and frequency scaling.

Great!

> > > A paper describing the proposal can be obtained from
> > > 
> > > http://www.research.ibm.com/arl/projects/dpm.html
> > > 
> > > A working prototype of the proposed framework for
> > > the IBM PowerPC 405LP processor exists and will be made
> > > public in the near future.
> > 
> > any idea if/how this will fit into the existing cross platform cpufreq
> > framework ?
> 
> It subsumes it, similar to Dominik's ideas in "[RFC] Dynamic Frequency
> and Voltage Scaling Infrastructure" (on the cpufreq list). The idea is
> that you want scaling events to be generated by the kernel rather than
> only scaling on userland input. The paper (and Dominik's mail) give you
> some ideas of when and why...

So, will it basically be a "policy governor" as described in my "[RFC]" mail?
Or does it need other enhancements in the cpufreq core? 

BTW, have you noticed the premilinary patch I which implements most of the 
DVS infrastructure mentioned in my mail to the cpufreq list yesterday?

	Dominik

Re: [Linux-pm-devel] Re: IBM/MontaVista Dynamic Power Management Project

[Hollis Blanchard]

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On Tue, 2002-12-03 at 14:00, Dominik Brodowski wrote:
> On Tue, Dec 03, 2002 at 12:27:03PM -0600, Hollis Blanchard wrote:
> > On Tue, 2002-12-03 at 11:57, Arjan van de Ven wrote:
> > > 
> > > any idea if/how this will fit into the existing cross platform cpufreq
> > > framework ?
> > 
> > It subsumes it, similar to Dominik's ideas in "[RFC] Dynamic Frequency
> > and Voltage Scaling Infrastructure" (on the cpufreq list). The idea is
> > that you want scaling events to be generated by the kernel rather than
> > only scaling on userland input. The paper (and Dominik's mail) give you
> > some ideas of when and why...
> 
> So, will it basically be a "policy governor" as described in my "[RFC]" mail?
> Or does it need other enhancements in the cpufreq core? 
> 
> BTW, have you noticed the premilinary patch I which implements most of the 
> DVS infrastructure mentioned in my mail to the cpufreq list yesterday?

Honestly I haven't had time to read it over and compare and contrast
with the IBM paper. From the sound of things though, I suspect both your
patch and the IBM code implement the same thing: an infrastructure
allowing "governors" to control dynamic scaling. The 405LP code also
includes such a governor of course. The ideas may be almost identical;
I'm not sure anyone's compared at this point. Do you have the time? ;)

-Hollis
-- 
PowerPC Linux
IBM Linux Technology Center

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Re: [Linux-pm-devel] Re: IBM/MontaVista Dynamic Power Management Project

[Dominik Brodowski]

On Tue, Dec 03, 2002 at 06:57:49PM +0100, Arjan van de Ven wrote:
> On Tue, 2002-12-03 at 18:46, Bishop Brock wrote:
> > IBM and MontaVista have initiated a joint project to develop a
> > dynamic power management control and policy mechanism for Linux
> > for processors supporting dynamic voltage and frequency scaling.
> > A paper describing the proposal can be obtained from
> > 
> > http://www.research.ibm.com/arl/projects/dpm.html
> > 
> > A working prototype of the proposed framework for
> > the IBM PowerPC 405LP processor exists and will be made
> > public in the near future.
> 
> any idea if/how this will fit into the existing cross platform cpufreq
> framework ?

Actually, if I understand IBM's proposal right, it seems to be an
alternative to cpufreq: a different "mid-layer" between the low-level
processor drivers, other kernel code, and the user. So it's not an extension
to an existing feature, but a new feature - Halloween was some weeks ago...

	Dominik

Re: IBM/MontaVista Dynamic Power Management Project

[Bishop Brock]

Alan Cox <alan@lxorguk.ukuu.org.uk> on 12/03/2002 12:39:56 PM
>> http://www.research.ibm.com/arl/projects/dpm.html
> Interesting. One small question however. The paper says "Others have
> also explored the possibilities of this type of fine grained control".
> More to the point however they have patents covering them. What does IBM
>intend to do about that ?

This is an important and complicated question.  Our code has passed an
internal IBM legal review,
however we are still discussing the implications of the patent with our
attorneys.
The best I can offer at this point is that we hope to have a definitive
answer next week.

The patent in question (US 6,298,448) deals with application-specific
dynamic scaling.
Although this is an important part of our proposal, it is not the central
idea, and I believe the
proposal has merit even if this portion were suppressed.