From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: Attempted summary of suspend-blockers LKML thread, take three Date: Sat, 14 Aug 2010 09:38:44 +0200 Message-ID: <20100814073843.GA27430@elf.ucw.cz> References: <20100809112453.77210acc@lxorguk.ukuu.org.uk> <20100809181638.GI3026@linux.vnet.ibm.com> <20100811222854.GJ2516@linux.vnet.ibm.com> <20100812010612.GL2516@linux.vnet.ibm.com> <20100812034435.GA7403@linux.vnet.ibm.com> <20100813115751.3bbbafbd@lxorguk.ukuu.org.uk> <20100813152912.GE2511@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20100813152912.GE2511@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Paul E. McKenney" Cc: david@lang.hm, Ted Ts'o , peterz@infradead.org, Brian Swetland , Felipe Contreras , linux-kernel@vger.kernel.org, James.Bottomley@suse.de, galibert@pobox.com, florian@mickler.org, menage@google.com, linux-pm@lists.linux-foundation.org, swmike@swm.pp.se, tglx@linutronix.de, Alan Cox , arjan@infradead.org List-Id: linux-pm@vger.kernel.org Hi! > > > > Think in terms of an ARM laptop. What good is opportunistic suspend if > > > > it's not going to help when the laptop is being used? > > > > > > For when the laptop is not being used, presumably. > > > > Or in time between keystrokes for most of the platform (backlight > > excepted). The Intel MID x86 devices are at the point that suspend/resume > > time on x86 is being hurt by the kernel rewriting smp alternatives as we > > go from 2 processors live to 1 and back. > > Given that you are talking about going from 2 processors to 1 and back, > I would guess that you are not actually talking about suspend/resume, > which is a system-wide thing rather than a CPU-by-CPU thing. I am not > sure whether you are using CPU hotplug or invoking SMP alternatives once > all but one CPU is idle. When entering system suspend, we disable non-boot-CPUs to simplify locking. We reenable them when going out of suspend. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html