From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@suse.cz (Pavel Machek) Date: Sun, 22 Feb 2009 15:23:51 +0100 Subject: [ltt-dev] [RFC git tree] Userspace RCU (urcu) for Linux (repost) In-Reply-To: <8bd0f97a0902132146t2badab79ue76e0a43d74c95ca@mail.gmail.com> References: <20090213155507.GA2838@Krystal> <20090213173352.GB4684@Krystal> <20090213185411.GB7124@Krystal> <20090213193619.GH6854@linux.vnet.ibm.com> <8bd0f97a0902132107r3651ce4rc5bc4e027268e2aa@mail.gmail.com> <20090214052030.GB7194@linux.vnet.ibm.com> <8bd0f97a0902132146t2badab79ue76e0a43d74c95ca@mail.gmail.com> Message-ID: <20090222142351.GG1586@ucw.cz> Hi! > > If Blackfin handles hotplug CPU, that may > > need attention as well, since tasks affinitied to the CPU being removed > > can end up with their affinity set to all CPUs. And there are probably > > other issues. > > no, we dont support hotplugging of CPUs. there is no hardware support > for it, so i think the only thing you'd gain is perhaps power savings > ? not sure it would even work in our case though as the hardware does > not support restarting or shutdown of one core ... they both have to > restart/shutdown. putting one core into a constant idle loop would > save power, but that can already be accomplished by reducing the apps > that go onto a specific core. Well, cpu hotplug is needed for suspend and hibernation... -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html