From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753929Ab0A0KA1 (ORCPT ); Wed, 27 Jan 2010 05:00:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753260Ab0A0KA1 (ORCPT ); Wed, 27 Jan 2010 05:00:27 -0500 Received: from one.firstfloor.org ([213.235.205.2]:57681 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753143Ab0A0KA0 (ORCPT ); Wed, 27 Jan 2010 05:00:26 -0500 Date: Wed, 27 Jan 2010 11:00:22 +0100 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , "Paul E. McKenney" , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com Subject: Re: [PATCH RFC tip/core/rcu] accelerate grace period if last non-dynticked CPU Message-ID: <20100127100022.GB12522@basil.fritz.box> References: <20100125034816.GA14043@linux.vnet.ibm.com> <873a1sft9q.fsf@basil.nowhere.org> <20100127052050.GC6807@linux.vnet.ibm.com> <20100127094336.GA12522@basil.fritz.box> <1264585850.4283.1992.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1264585850.4283.1992.camel@laptop> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 27, 2010 at 10:50:50AM +0100, Peter Zijlstra wrote: > On Wed, 2010-01-27 at 10:43 +0100, Andi Kleen wrote: > > > > Can't you simply check that at runtime then? > > > > if (num_possible_cpus() > 20) > > ... > > > > BTW the new small is large. This years high end desktop PC will come with > > upto 12 CPU threads. It would likely be challenging to find a good > > number for 20 that holds up with the future. > > If only scalability were that easy :/ See the rest of my email... I see you're already suffering from "Linus disease" ... only reading the first paragraph/sentence in the email. -Andi -- ak@linux.intel.com -- Speaking for myself only.