Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752685AbZCYX7U (ORCPT ); Wed, 25 Mar 2009 19:59:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752699AbZCYX7E (ORCPT ); Wed, 25 Mar 2009 19:59:04 -0400 Received: from gw.goop.org ([64.81.55.164]:38162 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752693AbZCYX7D (ORCPT ); Wed, 25 Mar 2009 19:59:03 -0400 Message-ID: <49CAC543.5020205@goop.org> Date: Wed, 25 Mar 2009 16:58:59 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Ravikiran G Thirumalai CC: Ingo Molnar , Yinghai Lu , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , "linux-kernel@vger.kernel.org" , shai@scalex86.org Subject: Re: [PATCH] x86: don't compile vsmp_64 for 32bit References: <20090227001757.GE27240@localdomain> <20090228094430.GH12095@elte.hu> <20090302235120.GF27240@localdomain> <20090322124818.GA31466@elte.hu> <20090324061429.GH7278@localdomain> <20090324091035.GA6605@elte.hu> <20090325185138.GI7278@localdomain> <49CAAD2E.3060904@goop.org> <20090325223642.GK7278@localdomain> <49CABB25.8040106@goop.org> <20090325232921.GL7278@localdomain> In-Reply-To: <20090325232921.GL7278@localdomain> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1110 Lines: 27 Ravikiran G Thirumalai wrote: > The point in this thread was, is_vsmp_box() needs to be meaningful even when > CONFIG_X86_VSMP is not on. This is needed because is_vsmp_box() is used to > determine if the platform has reliable tscs. > Well, as I said, that code is inoperative at present. But aside from that, how well will a non-VSMP kernel work on your hardware, with a normal cacheline, etc. Is the tsc stability really all that important, given that the kernel should notice if the tsc is busted pretty quickly anyway. unsynchronized_tsc() just returns a guess anyway, and if you don't have X86_FEATURE_CONSTANT_TSC set, then it will return unstable for your hardware anyway, even without the is_vsmp_box() test. Failing that, you could add yourself to bad_tsc_dmi_table[] and have that mark the tsc as unstable (you have DMI, right?). J -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/