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From: Pavel Machek <pavel@ucw.cz>
To: Vitaly Wool <vitalywool@gmail.com>
Cc: linux-pm@lists.osdl.org, Amit Kucheria <amit.kucheria@nokia.com>,
	Matthew Locke <matthew.a.locke@comcast.net>,
	scott.preece@motorola.com
Subject: Re: nokia 770 [was Re: community PM requirements/issues and PowerOP]
Date: Thu, 14 Dec 2006 14:56:10 +0000	[thread overview]
Message-ID: <20061214145609.GA4451@ucw.cz> (raw)
In-Reply-To: <acd2a5930612140501n3f287693i3670d836a82f9369@mail.gmail.com>


> >But what sense does it make for a user,sysadmin or 
> >application
> >to change voltage?  If any of these want to save power, 
> >they do so
> >by a) doing less work, and then b) lowering the clock 
> >speed as this
> >is inherently tied to voltage.
> 
> It makes sense to perform changing an operating point 
> dynamically in
> userland.

In very special cases, yes.

> That said, voltage should be accessible from userland.

Why?

If few states differ in voltage but not frequency, the only
user-visible thing is different latency of enter/exit.

If you only have two voltages per frequency (as it was shown in
examples here)... just add 1Hz to make difference between the two.

...but I guess you should teach cpufreq's ondemand governor to deal
with different latencies for different voltages. Before that is done
and shown to have significant power-saving impact, userspace interface
debate is useless.
							Pavel

-- 
Thanks for all the (sleeping) penguins.

  parent reply	other threads:[~2006-12-14 14:56 UTC|newest]

Thread overview: 134+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-11  7:57 community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Eugeny S. Mints
2006-09-11  8:20 ` Pavel Machek
2006-09-11  9:47   ` Eugeny S. Mints
2006-09-11 19:36     ` Pavel Machek
2006-09-11 19:53       ` Matthew Locke
2006-09-11 20:06         ` Pavel Machek
2006-09-11 20:09           ` Pavel Machek
2006-09-11 20:33             ` Matthew Locke
2006-09-11 21:06               ` Pavel Machek
2006-09-11 21:50                 ` Matthew Locke
2006-09-11 22:50                   ` Pavel Machek
2006-09-12  3:31                   ` Greg KH
2006-09-12  8:26                     ` Matthew Locke
2006-09-13  4:22                   ` David Brownell
2006-09-11 20:25           ` Matthew Locke
2006-09-11 21:02             ` Pavel Machek
2006-09-12  3:26             ` Greg KH
2006-09-11 22:00           ` Mark Gross
2006-09-11 22:08             ` Matthew Locke
2006-09-11 20:24       ` Eugeny S. Mints
2006-09-11 20:34         ` Pavel Machek
2006-09-13  4:54       ` David Brownell
2006-09-13 11:39         ` Preece Scott-PREECE
2006-09-14  9:12           ` Pavel Machek
2006-09-14  9:16             ` Vitaly Wool
2006-09-14  9:20             ` Matthew Locke
2006-09-14 10:05               ` Eugeny S. Mints
2006-09-14 10:17                 ` Pavel Machek
2006-09-14 10:47                   ` Eugeny S. Mints
2006-09-14 12:15                   ` Vitaly Wool
2006-09-14 13:03                     ` Pavel Machek
2006-09-14 13:04                       ` Pavel Machek
2006-09-14 13:15                       ` Vitaly Wool
2006-09-14 13:20                         ` Pavel Machek
2006-09-14 13:26                           ` Vitaly Wool
2006-09-14 14:59                           ` David Brownell
2006-09-17 10:53                           ` Amit Kucheria
2006-09-17 13:18                             ` Pavel Machek
2006-09-17 13:28                               ` Amit Kucheria
2006-09-17 13:40                                 ` Pavel Machek
2006-09-17 14:14                                   ` Amit Kucheria
2006-09-17 18:25                                     ` community PM requirements/issues and PowerOP[Was: " Preece Scott-PREECE
2006-09-18  9:02                                     ` community PM requirements/issues and PowerOP [Was: " Pavel Machek
2006-09-14 14:56                       ` David Brownell
2006-09-17 12:34                         ` Pavel Machek
2006-09-17 13:06                           ` Vitaly Wool
2006-09-18 10:46                           ` Amit Kucheria
2006-09-18 10:53                             ` Pavel Machek
2006-09-18 12:01                               ` Igor Stoppa
2006-09-18 12:11                                 ` nokia 770 [was Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]] Pavel Machek
2006-09-18 12:42                                   ` Amit Kucheria
2006-09-19 18:25                                     ` Pavel Machek
2006-12-12 20:00                                       ` nokia 770 [was Re: community PM requirements/issues and PowerOP] David Brownell
2006-12-13 12:12                                         ` Eugeny S. Mints
2006-12-13 21:03                                           ` Pavel Machek
2006-12-13 21:32                                             ` David Brownell
2006-12-13 21:44                                               ` Matthew Locke
2006-12-13 21:53                                                 ` Dave Jones
2006-12-13 22:50                                                   ` Matthew Locke
2006-12-13 22:58                                                     ` Dave Jones
2006-12-14 10:14                                                       ` Dmitry Krivoschekov
2006-12-14 12:12                                                         ` Dave Jones
2006-12-14 13:01                                                           ` Vitaly Wool
2006-12-14 13:17                                                             ` Dave Jones
2006-12-14 14:56                                                             ` Pavel Machek [this message]
2006-12-14 15:22                                                           ` Dmitry Krivoschekov
2006-12-13 22:55                                                 ` nokia 770 [was Re: community PM requirements...] David Brownell
2006-12-13 21:56                                               ` nokia 770 [was Re: community PM requirements/issues and PowerOP] Eugeny S. Mints
2006-12-13 21:58                                                 ` Pavel Machek
2006-12-13 22:27                                                 ` nokia 770 [was Re: community PM requirements...] David Brownell
2006-12-13 21:27                                         ` nokia 770 [was Re: community PM requirements/issues and PowerOP] Matthew Locke
2006-09-14 19:25                       ` community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Jon Loeliger
2006-09-17 12:46                         ` Pavel Machek
2006-09-17 17:32                           ` Preece Scott-PREECE
2006-09-19 18:20                             ` Pavel Machek
2006-09-19 19:11                               ` Preece Scott-PREECE
2006-09-23 23:39                                 ` Pavel Machek
2006-09-14 12:12                 ` Vitaly Wool
2006-09-14 12:35                   ` Eugeny S. Mints
2006-09-14  9:32             ` PowerOP on lkml or linux-pm? Matthew Locke
2006-09-14  9:45               ` Pavel Machek
2006-09-14  9:58                 ` Matthew Locke
2006-09-14  9:47             ` community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Matthew Locke
2006-09-11 19:30   ` Matthew Locke
2006-09-11 19:55     ` Pavel Machek
2006-09-11 20:53       ` Eugeny S. Mints
2006-09-11 21:00         ` Pavel Machek
2006-09-11 21:36           ` Preece Scott-PREECE
2006-09-11 21:39             ` Pavel Machek
2006-09-11 22:41               ` Eugeny S. Mints
2006-09-11 23:05                 ` cpufreq user<->kernel interface removal [was Re: community PM requirements/issues and PowerOP] Pavel Machek
2006-09-11 23:50                   ` Mark Gross
2006-09-12  3:35                     ` Greg KH
2006-09-12  8:41                       ` Matthew Locke
2006-09-12 17:03                       ` Jon Loeliger
2006-09-14 16:26                       ` Mark Gross
2006-09-17 12:37                         ` Pavel Machek
2006-09-17 13:10                           ` Vitaly Wool
2006-09-17 13:20                             ` Pavel Machek
2006-09-11 22:05           ` community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Eugeny S. Mints
2006-09-11 22:56             ` cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP] Pavel Machek
2006-09-12  0:17               ` Mark Gross
2006-09-12  3:37                 ` Greg KH
2006-09-13 23:50                   ` [linux-pm] " David Singleton
2006-09-14  5:30                     ` Vitaly Wool
2006-09-14  5:55                     ` OpPoint summary Greg KH
2006-09-14  7:35                       ` Vitaly Wool
2006-09-14 16:55                       ` David Singleton
2006-09-14 17:03                       ` David Singleton
2006-09-14 17:07                       ` David Singleton
2006-09-14 17:25                         ` Auke Kok
2006-09-14 18:15                           ` [linux-pm] " Vitaly Wool
2006-09-14 18:17                           ` David Singleton
2006-09-17 17:48                         ` Pavel Machek
2006-09-18 14:33                           ` [linux-pm] " Richard A. Griffiths
2006-09-18 16:13                             ` Matthew Locke
2006-09-14 17:11                       ` David Singleton
2006-09-17  5:07                       ` David Singleton
2006-09-17 12:56                         ` Pavel Machek
2006-09-17 12:58                         ` Pavel Machek
2006-09-17 22:43                         ` [linux-pm] " Matthew Locke
2007-02-27 20:55                     ` cpufreq terminally broken [was Re: community PM requirements/issues and PowerOP] David Brownell
2007-02-27 22:41                       ` Matthew Locke
2006-09-12  8:33                 ` Pavel Machek
2006-09-12  9:10                   ` Vitaly Wool
2006-09-12  9:16                     ` Pavel Machek
2006-09-12  9:23                       ` [linux-pm] " Vitaly Wool
2006-09-14 15:04                     ` Mark Gross
2006-09-14 14:58                   ` Mark Gross
2006-10-05  3:30             ` community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Dominik Brodowski
2006-09-11 21:53   ` Mark Gross
2006-09-11 22:43     ` Pavel Machek
2006-09-12  0:00       ` Mark Gross
  -- strict thread matches above, loose matches on Subject: below --
2006-12-14 14:16 nokia 770 [was Re: community PM requirements/issues and PowerOP] Scott E. Preece

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