From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754054AbZBIKQR (ORCPT ); Mon, 9 Feb 2009 05:16:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752450AbZBIKQC (ORCPT ); Mon, 9 Feb 2009 05:16:02 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:43654 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752452AbZBIKQA (ORCPT ); Mon, 9 Feb 2009 05:16:00 -0500 Date: Mon, 9 Feb 2009 11:15:52 +0100 From: Ingo Molnar To: "Pallipadi, Venkatesh" Cc: H Peter Anvin , Thomas Gleixner , linux-kernel Subject: Re: [PATCH] x86: Add clflush before monitor for Intel 7400 series - v2 Message-ID: <20090209101552.GF20467@elte.hu> References: <20090207005205.GB17586@linux-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090207005205.GB17586@linux-os.sc.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Pallipadi, Venkatesh wrote: > For Intel 7400 series CPUs, the recommendation is to use a clflush on the > monitored address just before monitor and mwait pair [1]. This clflush makes sure > that there are no false wakeups from mwait when the monitored address was recently > written to. > > [1] "MONITOR/MWAIT Recommendations for Intel Xeon Processor 7400 series" > section in specification update document of 7400 series > http://download.intel.com/design/xeon/specupdt/32033601.pdf > > Signed-off-by: Venkatesh Pallipadi > > --- > > Earlier patch: > http://marc.info/?l=linux-kernel&m=122341330606025&w=2 > > Current changes: > Minor modification based on Peter's comment > > arch/x86/include/asm/cpufeature.h | 1 + > arch/x86/kernel/cpu/intel.c | 3 +++ > arch/x86/kernel/process.c | 6 ++++++ > 3 files changed, 10 insertions(+) applied to tip/x86/urgent, thanks Venki! Ingo