From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755508AbaIBXW5 (ORCPT ); Tue, 2 Sep 2014 19:22:57 -0400 Received: from qmta11.emeryville.ca.mail.comcast.net ([76.96.27.211]:53542 "EHLO qmta11.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752365AbaIBXWz (ORCPT ); Tue, 2 Sep 2014 19:22:55 -0400 Date: Tue, 2 Sep 2014 18:22:52 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: "Paul E. McKenney" cc: Frederic Weisbecker , linux-kernel@vger.kernel.org Subject: Re: [RFC] dynticks: dynticks_idle is only modified locally use this_cpu ops In-Reply-To: <20140902211517.GO5001@linux.vnet.ibm.com> Message-ID: References: <20140902203743.GL5001@linux.vnet.ibm.com> <20140902211517.GO5001@linux.vnet.ibm.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Sep 2014, Paul E. McKenney wrote: > Yep, these two have been on my "when I am feeling insanely gutsy" list > for quite some time. > > But I have to ask... On x86, is a pair of mfence instructions really > cheaper than an atomic increment? Not sure why you would need an mfence instruction? > > If the first patch I send gets merged then a lot of other this_cpu related > > optimizations become possible regardless of the ones in the RFC. > > Yep, I am queuing that one. Great. > But could you please do future patches against the rcu/dev branch of > git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git? > I had to hand-apply due to conflicts. Please see below for my version, > and please check to make sure that I didn't mess something up in the > translation. Looks ok. Will use the correct tree next time.