From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755518Ab0KZRU5 (ORCPT ); Fri, 26 Nov 2010 12:20:57 -0500 Received: from mail-ww0-f44.google.com ([74.125.82.44]:41922 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751902Ab0KZRU4 (ORCPT ); Fri, 26 Nov 2010 12:20:56 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=MRrXTBwLyjAd1Bx9TBLYM3+LziJMq6Xwr47J6X9KhGFWv0e4xuqG4BUx2Xt8TO0KZs Ff8iCFPrfVBESMZCjmQBeS2FnHYL1yBdOPWzoi2wku4rcvA7XOr1fbtzDYYrYH39lbgo 3aR8IF2nY50QqesVoom0C6BVUF6btkjmr0wqM= Subject: Re: [PATCH] printk: use this_cpu_{read|write} api on printk_pending From: Eric Dumazet To: Christoph Lameter Cc: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, heiko.carstens@de.ibm.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: References: <20101126120235.406766476@de.ibm.com> <1290788536.2855.237.camel@edumazet-laptop> <1290790791.2855.259.camel@edumazet-laptop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 26 Nov 2010 18:20:51 +0100 Message-ID: <1290792051.2855.265.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le vendredi 26 novembre 2010 à 11:11 -0600, Christoph Lameter a écrit : > I thought sanity tests do not apply for performance testing scenarios? > CONFIG_DEBUG_PREEMPT > smp_processor_id() is usually a simple per cpu data access and very fast. > Sure, but when its already in a register, its better to use the register ;)