Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760081AbYBZEFx (ORCPT ); Mon, 25 Feb 2008 23:05:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754743AbYBZEFq (ORCPT ); Mon, 25 Feb 2008 23:05:46 -0500 Received: from server54.tchmachines.com ([72.9.244.106]:36592 "EHLO server54.tchmachines.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754009AbYBZEFp (ORCPT ); Mon, 25 Feb 2008 23:05:45 -0500 Date: Mon, 25 Feb 2008 20:05:41 -0800 From: Ravikiran Thirumalai To: Andi Kleen Cc: Yinghai Lu , Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , shai@scalemp.com Subject: Re: [PATCH] x86_64: make amd quad core 8 socket system not be clustered_box v2 Message-ID: <20080226040541.GK3143@localdomain> References: <200802210258.45011.yinghai.lu@sun.com> <200802221102.31019.yinghai.lu@sun.com> <47BF1BD9.4020808@firstfloor.org> <200802232148.43255.yinghai.lu@sun.com> <20080224122903.GC13637@one.firstfloor.org> <20080225190819.GE3143@localdomain> <86802c440802251405w7025a8b2na5fde4dcbf56067e@mail.gmail.com> <20080226033945.GJ3143@localdomain> <20080226034625.GE21577@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080226034625.GE21577@one.firstfloor.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - server54.tchmachines.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - scalemp.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1014 Lines: 26 On Tue, Feb 26, 2008 at 04:46:25AM +0100, Andi Kleen wrote: >> I don't quite understand the purpose of the patch to begin with. Looking at >> the current x86 git tree, apic_is_clustered_box is used only to determine if >> tsc is synchronized on the platform. The AMD docs imply that TSC's are not >> guaranteed to be synced across cores between nodes -- Opteron BKDG for >> family 10h, Section 2.9.4: > >After long discussions with AMD they determined the CPUID flag >for sync RDTSC will imply synchronization between nodes. Ah! > >If you can't support that in your hardware you're supposed >to clear it. Hmm! How would a hardware vendor do that? That doesn't seem to be clear in the BKDG. (Well, this is the problem with undocumented features :() Thanks, Kiran -- 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/