From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: suspend blockers & Android integration Date: Sat, 5 Jun 2010 15:23:26 -0700 Message-ID: <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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Arve =?UTF-8?B?SGrDuG5uZXbDpWc=?= 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" List-Id: linux-omap@vger.kernel.org On Sat, 5 Jun 2010 14:26:14 -0700 Arve Hj=C3=B8nnev=C3=A5g 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=C3=B8nnev=C3=A5g wrote: > >> > > Trusted processes are assumed to be sane and idle when there i= s > >> > > 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. > > >=20 > We clearly have different standards for what we consider good. We > measure time suspended in minutes or hours, not seconds, and waking u= p > 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 ;-) >=20 > > 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. >=20 > 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.=20 =46or 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. --=20 Arjan van de Ven Intel Open Source Technology Centre =46or development, discussion and tips for power savings,=20 visit http://www.lesswatts.org