From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: Does anyone use CONFIG_TINY_PREEMPT_RCU? Date: Tue, 13 Nov 2012 17:07:03 -0800 Message-ID: <20121114010703.GR2489@linux.vnet.ibm.com> References: <20121113004906.GA10557@linux.vnet.ibm.com> <201211132122.30259.tim01@vlsi.informatik.tu-darmstadt.de> <20121113212034.GD2489@linux.vnet.ibm.com> <201211140032.37320.tim01@vlsi.informatik.tu-darmstadt.de> <20121114000648.GN2489@linux.vnet.ibm.com> <20121114003641.GB7858@jtriplet-mobl1> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Tim Sander , linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org To: Josh Triplett Return-path: Content-Disposition: inline In-Reply-To: <20121114003641.GB7858@jtriplet-mobl1> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Tue, Nov 13, 2012 at 04:36:42PM -0800, Josh Triplett wrote: > On Tue, Nov 13, 2012 at 04:06:48PM -0800, Paul E. McKenney wrote: > > On Wed, Nov 14, 2012 at 12:32:36AM +0100, Tim Sander wrote: > > > Hi Paul > > > > > > Sorry english somehow i tried to shoehorn more than one sentence into one > > > sentence in the last mail. > > > > OK, how much memory does your device have? > > > It's 128Mb of memory. > > > > That is a bit on the smaller side. But still quite large compared > > to the 15K difference between CONFIG_TREE_PREEMPT_RCU and > > CONFIG_TINY_PREEMPT_RCU. > > I'd also expect CONFIG_TINY_PREEMPT_RCU to have marginally more > performance on a UP system, but probably not enough to matter. Agreed, I would expect this to be down in the noise. Thanx, Paul