From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262864AbVA2GYU (ORCPT ); Sat, 29 Jan 2005 01:24:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262865AbVA2GYU (ORCPT ); Sat, 29 Jan 2005 01:24:20 -0500 Received: from one.firstfloor.org ([213.235.205.2]:9698 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262864AbVA2GYR (ORCPT ); Sat, 29 Jan 2005 01:24:17 -0500 To: Venkatesh Pallipadi Cc: rohit.seth@intel.com, asit.k.mallick@intel.com, linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: [Discuss][i386] Platform SMIs and their interferance with tsc based delay calibration References: <20050128185101.A19117@unix-os.sc.intel.com> From: Andi Kleen Date: Sat, 29 Jan 2005 07:24:15 +0100 In-Reply-To: <20050128185101.A19117@unix-os.sc.intel.com> (Venkatesh Pallipadi's message of "Fri, 28 Jan 2005 18:51:01 -0800") Message-ID: User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Venkatesh Pallipadi writes: > + > + /* > + * If the upper limit and lower limit of the tsc_rate is more than > + * 12.5% apart. > + */ > + if (pre_start == 0 || pre_end == 0 || > + (tsc_rate_max - tsc_rate_min) > (tsc_rate_max >> 3)) { > + printk(KERN_WARNING "TSC calibration may not be precise. " > + "Too many SMIs? " > + "Consider running with \"lpj=\" boot option\n"); > + return 0; > + } I think it would be better to rerun it a few times automatically before giving up. This way it would hopefully work transparently but slower for most users. The message is too obscure too to be usable and needs more explanation. And also in case the platforms in questions support EM64T x86-64 would need to be changed too :) -Andi