Re: Plumbers: PM constraints micro-conf RFP

[mark gross <markgross@thegnar.org>]

On Tue, May 15, 2012 at 11:40:44AM +0200, Jean Pihet wrote:
> Hi!
> 
> Here is my proposal for the PM constraints micro-conf RFP, as e-mailed today:
> 
> Session title: A New Model for the System and Devices Latency
> 
> Name of microconference (if applicable): PM constraints micro-conf,
> led by Mark Gross
> 
> Abstract:
>  Due to the nature of the new SoC architectures the Power Management
> needs a new model for the various system latencies. The talk presents:
>   . the concepts of system, devices, wake-up and resume latencies,
>   . the recent changes in the devices framework for the latency, why
> and how to make it generic,
>   . the link with the other PM QoS frameworks: thermal, cpuidle,
>   . the recent changes in the ARM/OMAP platform code for the system latency,
>   . the problems encountered while modelling and measuring the
> various latencies,
>   . a proposal on the model and on the way to implement it,
>   . the planned changes in the device framework, the platform code
> and the APIs.
> 
>  This talk is oriented towards Linux power management developers. The
> goal is to agree on a framework implementation and the interfaces
> within the kernel and with the user space.

looks great to me!  you should toss it up on the plumbers site.

--mark


> Experience:
> Jean Pihet, NewOldBits.com
> 
> Jean Pihet is working with embedded Linux since many years now, for
> companies like Texas Instruments, MontaVista, Motorola and Philips.
> Recently NewOldBits.com has been founded to provide high quality
> consulting services. The area of work is mainly OMAP Power Management,
> tracing and profiling tools (perf, ftrace, oprofile...) for recent ARM
> cores.
> 
> Kind regards,
> Jean
> 
> On Tue, May 15, 2012 at 7:34 AM, Valentin, Eduardo
> <eduardo.valentin@ti.com> wrote:
> > FYI,
> >
> > I will submit later today, something like this:
> > "
> > Abstract
> >
> > The thermal challenge is to design an end-product with high
> > performance while keeping the junction temperature of the IC
> > components used on this product within their limitations and which
> > does not present a thermal discomfort for the user. OMAP4/OMAP5 System
> > on Chips, operating at highest Operating Performance Points (OPP), is
> > a powerful mobile applications processor. However operating at higher
> > voltage and higher frequency in a sustained manner may cause thermal
> > limits to be exceeded, both for silicon and user comfort. We propose a
> > new framework to model per device power constraints, for containment
> > of thermal limitations across major heat sources of a end-product
> > device, e.g. LCD, CPU, charging, etc. The framework shall facilitate
> > the power and thermal management performed by governor and policies,
> > depending on device context and use case knowledge.
> >
> > Authors
> >
> > Eduardo Valentin, System Software Engineer at Texas Instruments,
> > working on OMAP Linux kernel, previously a working on power management
> > in maemo for Nokia.
> >
> >
> > On Tue, May 15, 2012 at 8:06 AM, Valentin, Eduardo
> > <eduardo.valentin@ti.com> wrote:
> >> Benoit,
> >>
> >> On Mon, May 14, 2012 at 8:11 PM, Cousson, Benoit <b-cousson@ti.com> wrote:
> >>> Hi Jean,
> >>>
> >>>
> >>> On 5/14/2012 2:45 PM, Jean Pihet wrote:
> >>>>
> >>>> Hi Benoit,
> >>>>
> >>>> On Fri, May 11, 2012 at 9:17 AM, Valentin, Eduardo
> >>>> <eduardo.valentin@ti.com>  wrote:
> >>>>>
> >>>>> Hello Mark,
> >>>>>
> >>>>> On Wed, May 2, 2012 at 5:36 PM, mark gross<markgross@thegnar.org>  wrote:
> >>>>>>
> >>>>>> This is a Request For Participation in a micro-conference at this years
> >>>>>> Linux plumbers event.  For this micro conference to happen we need to
> >>>>>> reach a certain critical mass WRT participants as measured by submitted
> >>>>>> talks associated to Power Management Constraints.
> >>>>>
> >>>>>
> >>>>> Nice! Thanks for proposing this.
> >>>>>
> >>>>>>
> >>>>>> The To: list is populated with folks that I've had interactions with
> >>>>>> over extending pm-qos or constraint based PM over the past year.
> >>>>>>
> >>>>>> If you are working on problems related to constraining the power /
> >>>>>> performance of devices I am inviting your participation and request you
> >>>>>> submit a proposal for presenting your problem space (preferred) and or
> >>>>>> solution to a group of developers looking for a good solution to push
> >>>>>> upstream.  The talks will be about 20 min long as I want to get into
> >>>>>> some design and implementation discussions after the requirements
> >>>>>> definition is mostly finished.
> >>>>
> >>>> Is it OK to submit a talk for the next LPC? The deadline is tomorrow IIRC.
> >>>
> >>>
> >>> Yes, it is. Go ahead. It is related to Mark's proposal? Because it seems we
> >>> have to do some homework in order to participate to the micro-conf :-(.
> >>
> >> Yes, the homework is required in order to drive the discussion based
> >> on existing usable solutions..
> >>
> >> Jean, I'll write down a proposal today, from thermal requirements
> >> perspective. But we can discuss also a way to converge either in a
> >> common presentation or in even with two presentations but with strong
> >> linking together.
> >>
> >> Just trying to avoid two conflicting proposals from two peers @ti.com
> >>
> >>>
> >>> Regards,
> >>> Benoit
> >>>
> >>>
> >>>>
> >>>> Regards,
> >>>> Jean
> >>>>
> >>>>>>
> >>>>>> I am interested in gathering user mode interface needs as well as kernel
> >>>>>> mode.
> >>>>>>
> >>>>>>  From a high level pm-constraints is a generalization of pm-qos to
> >>>>>> include
> >>>>>> limiting performance as well as its current limiting of device
> >>>>>> throttling.
> >>>>>>
> >>>>>> As performance limiting is typically used for any of the following:
> >>>>>> 1) staying within thermal operational envelopes
> >>>>>> 2) avoiding peak current
> >>>>>> 3) extending battery life in active use cases
> >>>>>>
> >>>>>> I invite anyone working in any of these areas or pm-qos applications to
> >>>>>> participate in this micro-conference.
> >>>>>>
> >>>>>> I will organize the micro-conference into 2 parts:
> >>>>>> 1) problem statements with specific participant examples where
> >>>>>> constraining the performance or throttling is needed.
> >>>>>
> >>>>>
> >>>>>
> >>>>> I could bring something on the use cases where this type of
> >>>>> constraining could be used. Essentially major focus gets partitioned
> >>>>> in two areas: For device skin/case temperature management, and IC's
> >>>>> junction temperature management.
> >>>>>
> >>>>> I am currently checking the traveling arrangements as well. And
> >>>>> confirming soon.
> >>>>>
> >>>>>
> >>>>>>
> >>>>>> 2) high level design brain storming.
> >>>>>>
> >>>>>> If the micro-conference happens (i.e. critical mass is reached) any
> >>>>>> interested linux-plumbers attendees is very welcome to participate.
> >>>>>>
> >>>>>> Please send me an off list email if you want me to add you to my mutt
> >>>>>> alias of interested parties I'll use to cc people on emails.  Note: must
> >>>>>> of the correspondence will cc linux-pm too.
> >>>>>>
> >>>>>> Please submit a proposal if you are interested in participating in this
> >>>>>> with me.  I know a number of people are working in this space for the
> >>>>>> past few years now.  I think its a good time to compare notes and at
> >>>>>> least consolidate requirements and use cases.  Perhaps we'll even come
> >>>>>> up
> >>>>>> with a good design to implement in the process.
> >>>>>>
> >>>>>> thanks,
> >>>>>> --mark
> >>>>>>
> >>>>>
> >>>>>
> >>>>> All best,
> >>>>> --
> >>>>>
> >>>>> Eduardo Valentin
> >>>>> _______________________________________________
> >>>>> linux-pm mailing list
> >>>>> linux-pm@lists.linux-foundation.org
> >>>>> https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
> >>>
> >>>
> >>
> >>
> >>
> >> --
> >>
> >> Eduardo Valentin
> >
> >
> >
> > --
> >
> > Eduardo Valentin