Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933480Ab0FEWjq (ORCPT ); Sat, 5 Jun 2010 18:39:46 -0400 Received: from mail-px0-f174.google.com ([209.85.212.174]:39209 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933381Ab0FEWjo convert rfc822-to-8bit (ORCPT ); Sat, 5 Jun 2010 18:39:44 -0400 MIME-Version: 1.0 In-Reply-To: <20100605152326.7ccd5160@infradead.org> References: <20100603193045.GA7188@elte.hu> <20100603231153.GA11302@elte.hu> <20100603232302.GA16184@elte.hu> <20100604071354.GA14451@elte.hu> <20100604083423.GD15181@elte.hu> <1275653210.27810.39762.camel@twins> <1275731653.27810.41078.camel@twins> <20100605092851.6ee15f13@infradead.org> <20100605152326.7ccd5160@infradead.org> Date: Sat, 5 Jun 2010 15:39:44 -0700 Message-ID: Subject: Re: suspend blockers & Android integration From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= To: Arjan van de Ven Cc: Peter Zijlstra , Ingo Molnar , tytso@mit.edu, Brian Swetland , Neil Brown , Thomas Gleixner , "Rafael J. Wysocki" , Alan Stern , Felipe Balbi , LKML , Florian Mickler , Linux OMAP Mailing List , Linux PM , Alan Cox , James Bottomley , Linus Torvalds , Kevin Hilman , "H. Peter Anvin" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2416 Lines: 63 2010/6/5 Arjan van de Ven : > On Sat, 5 Jun 2010 14:26:14 -0700 > Arve Hj?nnev?g wrote: > >> On Sat, Jun 5, 2010 at 9:28 AM, Arjan van de Ven >> wrote: >> > On Sat, 05 Jun 2010 11:54:13 +0200 >> > Peter Zijlstra wrote: >> > >> >> On Fri, 2010-06-04 at 17:10 -0700, Arve Hj?nnev?g wrote: >> >> > > Trusted processes are assumed to be sane and idle when there is >> >> > > nothing for them to do, allowing the machine to go into deep >> >> > > idle states. >> >> > > >> >> > >> >> > Neither the kernel nor our trusted user-space code currently >> >> > meets this criteria. >> >> >> >> Then both need fixing. Really, that's the only sane approach. >> > >> > fwiw... in MeeGo we're seeing quite good idle times (> 1 seconds) >> > without really bad hacks. >> > >> >> We clearly have different standards for what we consider good. We >> measure time suspended in minutes or hours, not seconds, and waking up >> every second or two causes a noticeable decrease in battery life on >> the hardware we have today. > > I guess I'm spoiled working with (unreleased) hardware that knows how > to power gate ;-) > > >> >> > the kernel has a set of infrastructure already to help here (range >> > timers, with which you can wakeup-limit untrusted userspace crap), >> > timer slack for legacy background timers, etc etc. >> >> Range timers allows the kernel to align different timers so they don't >> each bring the cpu out of idle individually. They do not eliminate >> timers or make individual timers fire less often. > > you're incorrect. > With range timers you can control the rate at which timers fire just > fine. > > For example if the Adobe Flash player puts a timer every 10 > milliseconds (yes it does that), and you give it a 3.99 seconds range, > it will fire its timers every 4 seconds.... unless other activity > happens independently, at which point it'll align with that instead. > If you do that what you are delivering is nowhere close to what the app asked for. You don't need range timers for this, you could just as well add 4 seconds to all normal timers. -- Arve Hj?nnev?g -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/