From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756377Ab3J1Kbg (ORCPT ); Mon, 28 Oct 2013 06:31:36 -0400 Received: from mail-ea0-f178.google.com ([209.85.215.178]:46143 "EHLO mail-ea0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754581Ab3J1Kbf (ORCPT ); Mon, 28 Oct 2013 06:31:35 -0400 Date: Mon, 28 Oct 2013 11:31:32 +0100 From: Ingo Molnar To: Borislav Petkov Cc: Andreas Werner , tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, dave@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] X86: MM: Add PAT Type write-through in combination with mtrr Message-ID: <20131028103132.GA6274@gmail.com> References: <1382878525-3410-1-git-send-email-wernerandy@gmx.de> <20131027133401.GB24817@pd.tnic> <20131027165159.GD1617@thinkpad.fritz.box> <20131027173131.GC21868@pd.tnic> <20131027175608.GA1340@thinkpad.fritz.box> <20131027190148.GD21868@pd.tnic> <20131028062946.GA1391@thinkpad.fritz.box> <20131028101749.GA4389@gmail.com> <20131028102938.GD4314@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131028102938.GD4314@pd.tnic> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Borislav Petkov wrote: > On Mon, Oct 28, 2013 at 11:17:49AM +0100, Ingo Molnar wrote: > > > And regular write-back cacheable isn't sufficient because the > > CPU could do things like prefetch your range automatically? > > Yeah, he's doing a CLFLUSH anyway which basically makes it a > write-through... The CLFLUSH is done afterwards (making it a use-once thing), so WB might still be faster and would avoid the PAT headache ... Thanks, Ingo