2010/6/5 Arjan van de Ven <arjan@xxxxxxxxxxxxx>: > On Sat, 5 Jun 2010 14:26:14 -0700 > Arve Hjønnevåg <arve@xxxxxxxxxxx> wrote: > >> On Sat, Jun 5, 2010 at 9:28 AM, Arjan van de Ven >> <arjan@xxxxxxxxxxxxx> wrote: >> > On Sat, 05 Jun 2010 11:54:13 +0200 >> > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: >> > >> >> On Fri, 2010-06-04 at 17:10 -0700, Arve Hjønnevåg 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 Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
