From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754622AbYDMUu6 (ORCPT ); Sun, 13 Apr 2008 16:50:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751198AbYDMUuv (ORCPT ); Sun, 13 Apr 2008 16:50:51 -0400 Received: from one.firstfloor.org ([213.235.205.2]:35257 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751026AbYDMUuu (ORCPT ); Sun, 13 Apr 2008 16:50:50 -0400 Message-ID: <48027225.6000609@firstfloor.org> Date: Sun, 13 Apr 2008 22:50:45 +0200 From: Andi Kleen User-Agent: Thunderbird 1.5.0.12 (X11/20060911) MIME-Version: 1.0 To: "H. Peter Anvin" CC: Erik Bosman , Andrew Morton , Thomas Gleixner , Ingo Molnar , Arjan van de Ven , Andrea Arcangeli , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] Add prctl commands PR_GET_TSC and PR_SET_TSC References: <87r6daw2ay.fsf@basil.nowhere.org> <87prstwvkr.fsf@basil.nowhere.org> <48025F1B.10701@zytor.com> In-Reply-To: <48025F1B.10701@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > I think what Erik is trying to do is to make it possible to disable as > many of these in the kernel as possible; I/O is easy, it's off by > default; RDTSC and RDPMC can be disabled in the kernel, and I think > even XSTORE can be disabled. I'm a little sceptical it will work reliably, but we'll see. There's also LSL (forgot that earlier). It is used by the vgetcpu() because it's faster than CPUID or RDTSCP. Kernel sets a magic segment up which has different limits for different CPUs. -Andi