From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757033Ab0ERLZV (ORCPT ); Tue, 18 May 2010 07:25:21 -0400 Received: from one.firstfloor.org ([213.235.205.2]:58916 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752708Ab0ERLZT (ORCPT ); Tue, 18 May 2010 07:25:19 -0400 Date: Tue, 18 May 2010 13:25:10 +0200 From: Andi Kleen To: Peter Zijlstra Cc: Arjan van de Ven , Dan Magenheimer , Thomas Gleixner , Andi Kleen , Venkatesh Pallipadi , Ingo Molnar , "H. Peter Anvin" , chris.mason@oracle.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: Export tsc related information in sysfs Message-ID: <20100518112509.GD22675@basil.fritz.box> References: <1273887635-27610-1-git-send-email-venki@google.com> <87tyq9mqrz.fsf@basil.nowhere.org> <35aa841b-e151-424d-b1c1-0c03dbcae5cc@default> <20100515121424.38f5b389@infradead.org> <20100515224305.17a04022@infradead.org> <5adf3fee-0f7b-4039-b13f-619640cc4b88@default> <20100516220638.2baf315d@infradead.org> <1274176698.5605.7358.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1274176698.5605.7358.camel@twins> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 18, 2010 at 11:58:18AM +0200, Peter Zijlstra wrote: > On Sun, 2010-05-16 at 22:06 -0700, Arjan van de Ven wrote: > > look we're not disabling ring 3 tsc. We could, but we don't. > > Maybe we should. That would kill the vsyscall too. Remember it's running in ring 3. That is in theory you could disable it on systems where the vsyscall doesn't use it, but then you would likely break huge amounts of software, unless you emulate it. Emulation would be a possibility, but I'm not sure it would make anyone really happy. It would be certainly slow. -Andi -- ak@linux.intel.com -- Speaking for myself only.