From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752874Ab2KPSKU (ORCPT ); Fri, 16 Nov 2012 13:10:20 -0500 Received: from e8.ny.us.ibm.com ([32.97.182.138]:40220 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752462Ab2KPSKT (ORCPT ); Fri, 16 Nov 2012 13:10:19 -0500 Date: Fri, 16 Nov 2012 10:09:56 -0800 From: "Paul E. McKenney" To: Christoph Lameter Cc: Shan Wei , dipankar@in.ibm.com, Kernel-Maillist , Tejun Heo Subject: Re: [PATCH v3 6/9] rcu: use __this_cpu_read helper instead of per_cpu_ptr(p, raw_smp_processor_id()) Message-ID: <20121116180956.GE3270@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <50A1A7E8.4010802@gmail.com> <50A5FA32.4000903@gmail.com> <20121116164337.GD3270@linux.vnet.ibm.com> <0000013b0a505095-87cdf6aa-4e22-4439-9fe2-5c93044077ff-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000013b0a505095-87cdf6aa-4e22-4439-9fe2-5c93044077ff-000000@email.amazonses.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12111618-9360-0000-0000-00000CE282FF Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 16, 2012 at 05:42:14PM +0000, Christoph Lameter wrote: > > On Fri, 16 Nov 2012, Paul E. McKenney wrote: > > > If you either show me some significant performance benefits or get me > > an independent Tested-by, in both cases on a range of hardware (e.g., > > x86 on the one hand and ARM or Power on the other), then I will queue it. > > Just putting the code generated for x86 before and after side > by side would be enough to convince you I think. If accompanied by similar before/after code for ARM or Power, sure. Thanx, Paul > > I wasn't prioritizing this one very high because it does not appear > > to be on any sort of fastpath. If I am wrong about that, then you > > have a good performance-benefit case, right? ;-) > > I do not think this needs to be a priority item. Just stick it in the tree > somewhere to merge for the next merge period. >