Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Len Brown]

We'll be in The Rideau Suite in Les-Suites
Tuesday July 22nd 8:30-18:30.

Thanks to HP for sponsoring
lunch at 12:30 as well as snacks at 10:00 and 15:30.
We'll wing it for dinner.

On linux-pm (sorry, on sabbatical I've been
bad about keeping up on email) I've seen
intent to attend from:

Len Brown <len.brown@intel.com>
Alan Stern <stern@rowland.harvard.edu>
Dipankar Sarma <dipankar@in.ibm.com>
Rafael J. Wysocki <rjw@sisk.pl>
"Woodruff, Richard" <r-woodruff2@ti.com>
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Matt Domsch <Matt_Domsch@dell.com>
Jarod Wilson <jwilson@redhat.com>
Tim Bird <tim.bird@am.sony.com>
Paul Mundt <lethal@linux-sh.org>
Hiroyuki Machida <Hiroyuki.Mach@gmail.com>

Several send their regrets:
Dave Jones
Pavel Machek
Arjan van de Ven

If you plan to attend, please let me know,
because the folks at OLS want to know,
to simplify OLS registration.

thanks,
-Len
---

We are again planning a Linux Power Management Mini-Summit preceding OLS.
This year we are looking at a single day, Tuesday July 22nd.

OLS is generously supporting mini-summits by providing the room
and projector: http://www.linuxsymposium.org/2008/minisummits.php

If you are interested in sponsoring the food or
other forum needs, please let me know.

Minutes from last year's meeting can be found here:
http://lwn.net/Articles/249019

If you have feedback on last year's meeting that
we can use to improve this year's, please speak up.

The feedback at the time was pretty positive, so I'm thinking
that unless there are new best-known-methods, that we'll stick
with the same open method of self-nominated attendees,
an agenda provoked by discussion on linux-pm ahead of time
and consensus of attendees, and a forum small enough to support
a single focused discussion.

(yes, one improvement I plan on this year is to publish minutes immediately.
 OLS was sort of hectic for me last year and that caused a delay)

thanks,
-Len

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Nigel Cunningham]

Hi.

On Thu, 2008-07-17 at 17:27 -0400, Len Brown wrote:
> We'll be in The Rideau Suite in Les-Suites
> Tuesday July 22nd 8:30-18:30.
> 
> Thanks to HP for sponsoring
> lunch at 12:30 as well as snacks at 10:00 and 15:30.
> We'll wing it for dinner.
> 
> On linux-pm (sorry, on sabbatical I've been
> bad about keeping up on email) I've seen
> intent to attend from:
> 
> Len Brown <len.brown@intel.com>
> Alan Stern <stern@rowland.harvard.edu>
> Dipankar Sarma <dipankar@in.ibm.com>
> Rafael J. Wysocki <rjw@sisk.pl>
> "Woodruff, Richard" <r-woodruff2@ti.com>
> Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
> Matt Domsch <Matt_Domsch@dell.com>
> Jarod Wilson <jwilson@redhat.com>
> Tim Bird <tim.bird@am.sony.com>
> Paul Mundt <lethal@linux-sh.org>
> Hiroyuki Machida <Hiroyuki.Mach@gmail.com>
> 
> Several send their regrets:
> Dave Jones
> Pavel Machek
> Arjan van de Ven

Nigel Cunningham

> If you plan to attend, please let me know,
> because the folks at OLS want to know,
> to simplify OLS registration.

Regards,

Nigel

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Vaidyanathan Srinivasan]

* Len Brown <lenb@kernel.org> [2008-07-17 17:27:32]:

> We'll be in The Rideau Suite in Les-Suites
> Tuesday July 22nd 8:30-18:30.
> 
> Thanks to HP for sponsoring
> lunch at 12:30 as well as snacks at 10:00 and 15:30.
> We'll wing it for dinner.
> 
> On linux-pm (sorry, on sabbatical I've been
> bad about keeping up on email) I've seen
> intent to attend from:
> 
> Len Brown <len.brown@intel.com>
> Alan Stern <stern@rowland.harvard.edu>
> Dipankar Sarma <dipankar@in.ibm.com>
> Rafael J. Wysocki <rjw@sisk.pl>
> "Woodruff, Richard" <r-woodruff2@ti.com>
> Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
> Matt Domsch <Matt_Domsch@dell.com>
> Jarod Wilson <jwilson@redhat.com>
> Tim Bird <tim.bird@am.sony.com>
> Paul Mundt <lethal@linux-sh.org>
> Hiroyuki Machida <Hiroyuki.Mach@gmail.com>
> 
> Several send their regrets:
> Dave Jones
> Pavel Machek
> Arjan van de Ven
> 
> If you plan to attend, please let me know,

Hi Len,

Thanks for including me.  I will attend the mini summit.

--Vaidy

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Gautham R Shenoy]

On Thu, Jul 17, 2008 at 05:27:32PM -0400, Len Brown wrote:
> We'll be in The Rideau Suite in Les-Suites
> Tuesday July 22nd 8:30-18:30.
> 
> Thanks to HP for sponsoring
> lunch at 12:30 as well as snacks at 10:00 and 15:30.
> We'll wing it for dinner.
> 
> On linux-pm (sorry, on sabbatical I've been
> bad about keeping up on email) I've seen
> intent to attend from:
> 
> Len Brown <len.brown@intel.com>
> Alan Stern <stern@rowland.harvard.edu>
> Dipankar Sarma <dipankar@in.ibm.com>
> Rafael J. Wysocki <rjw@sisk.pl>
> "Woodruff, Richard" <r-woodruff2@ti.com>
> Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
> Matt Domsch <Matt_Domsch@dell.com>
> Jarod Wilson <jwilson@redhat.com>
> Tim Bird <tim.bird@am.sony.com>
> Paul Mundt <lethal@linux-sh.org>
> Hiroyuki Machida <Hiroyuki.Mach@gmail.com>
> 
Hi Len,
I would like to attend the pm-mini summit if there's a slot available. I
am interested in discussing:

a) the improvements to idle load balancing
algorithm on multi-node multi-core systems, for better power savings.

b) Use of some kind of light-weight CPU-Hotplug for power-management
on server systems.

> Several send their regrets:
> Dave Jones
> Pavel Machek
> Arjan van de Ven
> 
> If you plan to attend, please let me know,
> because the folks at OLS want to know,
> to simplify OLS registration.
> 
> thanks,
> -Len
> ---
> 
> We are again planning a Linux Power Management Mini-Summit preceding OLS.
> This year we are looking at a single day, Tuesday July 22nd.
> 
> OLS is generously supporting mini-summits by providing the room
> and projector: http://www.linuxsymposium.org/2008/minisummits.php
> 
> If you are interested in sponsoring the food or
> other forum needs, please let me know.
> 
> Minutes from last year's meeting can be found here:
> http://lwn.net/Articles/249019
> 
> If you have feedback on last year's meeting that
> we can use to improve this year's, please speak up.
> 
> The feedback at the time was pretty positive, so I'm thinking
> that unless there are new best-known-methods, that we'll stick
> with the same open method of self-nominated attendees,
> an agenda provoked by discussion on linux-pm ahead of time
> and consensus of attendees, and a forum small enough to support
> a single focused discussion.
> 
> (yes, one improvement I plan on this year is to publish minutes immediately.
>  OLS was sort of hectic for me last year and that caused a delay)
> 
> thanks,
> -Len
> 
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.linux-foundation.org
> https://lists.linux-foundation.org/mailman/listinfo/linux-pm

-- 
Thanks and Regards
gautham

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Pavel Machek]

On Fri 2008-07-18 04:50:00, Gautham R Shenoy wrote:
> On Thu, Jul 17, 2008 at 05:27:32PM -0400, Len Brown wrote:
> > We'll be in The Rideau Suite in Les-Suites
> > Tuesday July 22nd 8:30-18:30.
> > 
> > Thanks to HP for sponsoring
> > lunch at 12:30 as well as snacks at 10:00 and 15:30.
> > We'll wing it for dinner.
> > 
> > On linux-pm (sorry, on sabbatical I've been
> > bad about keeping up on email) I've seen
> > intent to attend from:
> > 
> > Len Brown <len.brown@intel.com>
> > Alan Stern <stern@rowland.harvard.edu>
> > Dipankar Sarma <dipankar@in.ibm.com>
> > Rafael J. Wysocki <rjw@sisk.pl>
> > "Woodruff, Richard" <r-woodruff2@ti.com>
> > Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
> > Matt Domsch <Matt_Domsch@dell.com>
> > Jarod Wilson <jwilson@redhat.com>
> > Tim Bird <tim.bird@am.sony.com>
> > Paul Mundt <lethal@linux-sh.org>
> > Hiroyuki Machida <Hiroyuki.Mach@gmail.com>
> > 
> Hi Len,
> I would like to attend the pm-mini summit if there's a slot available. I
> am interested in discussing:
> 
> a) the improvements to idle load balancing
> algorithm on multi-node multi-core systems, for better power savings.
> 
> b) Use of some kind of light-weight CPU-Hotplug for power-management
> on server systems.

Step one, fix cpu hotplug not to eat more power than idle cpu...?

I wonder, how can cpu hotplug help, relative to inteligent scheduler?
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Len Brown]

This is an open invitation to participate in
a Linux Power Management mini-summit
9AM Tuesday July 22, 2008 in Ottawa.

This is the day before the Ottawa Linux Symposium.
OLS is generously supporting Linux mini-summits by providing the room
and projector: http://www.linuxsymposium.org/2008/minisummits.php

The meeting format will be round-table discussion.
There will be no phone bridge or audio/video recording.
However, there will be written minutes as there
were last year:  http://lwn.net/Articles/249019

Send suggestions for topics to linux-pm@lists.osdl.org,
whether you plan to attend or not.  The attendees will
form the agenda by consensus at the start of the session.

If you would like to attend, please send a note to
linux-pm@lists.osdl.org announcing your intent,
and what you would like to discuss.

Last year we were were cautious about presentations, for fear they
would not support discussion.  But the short ones we had actually
facilitied discussion, so we'll allow them again this year.

thanks,
-Len

ps. There is an opportunity for your company to help sponsor
the event -- for right now we are on our own for food.
If you are interseted, please contact me and OLS.

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Nigel Cunningham]

Hi.

On Wed, 2008-06-25 at 14:44 -0400, Len Brown wrote:
> This is an open invitation to participate in
> a Linux Power Management mini-summit
> 9AM Tuesday July 22, 2008 in Ottawa.
> 
> This is the day before the Ottawa Linux Symposium.
> OLS is generously supporting Linux mini-summits by providing the room
> and projector: http://www.linuxsymposium.org/2008/minisummits.php
> 
> The meeting format will be round-table discussion.
> There will be no phone bridge or audio/video recording.
> However, there will be written minutes as there
> were last year:  http://lwn.net/Articles/249019
> 
> Send suggestions for topics to linux-pm@lists.osdl.org,
> whether you plan to attend or not.  The attendees will
> form the agenda by consensus at the start of the session.
> 
> If you would like to attend, please send a note to
> linux-pm@lists.osdl.org announcing your intent,
> and what you would like to discuss.
> 
> Last year we were were cautious about presentations, for fear they
> would not support discussion.  But the short ones we had actually
> facilitied discussion, so we'll allow them again this year.
> 
> thanks,
> -Len
> 
> ps. There is an opportunity for your company to help sponsor
> the event -- for right now we are on our own for food.
> If you are interseted, please contact me and OLS.

All I can say is "Have fun, guys." I'm interested in developments, and
would love to contribute but there's no way I'd be able to get there and
I have little time to do anything.

I'd be interested (of course) to hear the fruit of discussions re
hibernation.

Regards,

Nigel

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Alan Stern]

On Wed, 25 Jun 2008, Len Brown wrote:

> If you would like to attend, please send a note to
> linux-pm@lists.osdl.org announcing your intent,
> and what you would like to discuss.

I plan to attend, and my proposed topic is Runtime PM implementation.

Alan Stern

Re: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Rafael J. Wysocki]

On Thursday, 26 of June 2008, Alan Stern wrote:
> On Wed, 25 Jun 2008, Len Brown wrote:
> 
> > If you would like to attend, please send a note to
> > linux-pm@lists.osdl.org announcing your intent,
> > and what you would like to discuss.
> 
> I plan to attend, and my proposed topic is Runtime PM implementation.

That sounds interesting. :-)

Rafael

RE: [linux-pm] Linux Power Management Mini-Summit -- Ottawa -- July 22, 2008

[Woodruff, Richard]

> Send suggestions for topics to linux-pm@lists.osdl.org,
> whether you plan to attend or not.  The attendees will
> form the agenda by consensus at the start of the session.
>
> If you would like to attend, please send a note to
> linux-pm@lists.osdl.org announcing your intent,
> and what you would like to discuss.

I would like to attend.

Main topics of interest would be run time PM.

We currently have ARM systems using cpuidle and going to 0v with full context loss between dynamic ticks.  There are a few areas it would be nice to get feed back on some hacks have had to be employed to get reasonable performance.

For example:
- we are saving driver state based on aggressive clock disables in drivers and only restoring context back on enable on control or event paths.  Doing this at the bottom of a driver stack like MMC means you don't always have good knowledge of what the stack has in store.  As such we add some activity timers to smooth it out.  But it would be nice to have some kind of idea about upper layer activity.

- With dynamic tick running you find needless one shot timer reprogramming (mainly from high interrupts during idle).  This can overflow the timer posting buffer and stall the MPU to a slower clock domain.  This results in really bad throughput.  Just keeping user space active and the periodic timer running instead of 1-shot will result in much better performance.

- How to account for demoted C-States?  Right now if a CPUIDLE BM check forces a state reduction compared to the menu governor chosen C-State there is no path to allow for residency accounting for the actual state entered.

Thanks,
Richard W.