From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755371AbZHTUy0 (ORCPT ); Thu, 20 Aug 2009 16:54:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753908AbZHTUyZ (ORCPT ); Thu, 20 Aug 2009 16:54:25 -0400 Received: from g5t0007.atlanta.hp.com ([15.192.0.44]:33894 "EHLO g5t0007.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752710AbZHTUyZ (ORCPT ); Thu, 20 Aug 2009 16:54:25 -0400 Date: Thu, 20 Aug 2009 14:54:25 -0600 From: Alex Chiang To: Suresh Siddha Cc: "hpa@zytor.com" , "mingo@redhat.com" , "tglx@linutronix.de" , "andi@firstfloor.org" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: add /proc/cpuinfo/physical id quirks Message-ID: <20090820205425.GF13061@ldl.fc.hp.com> References: <20090814163618.GQ7185@ldl.fc.hp.com> <1250276831.3077.17.camel@sbs-t61.sc.intel.com> <20090814192730.GA6431@ldl.fc.hp.com> <1250279799.3077.41.camel@sbs-t61.sc.intel.com> <20090819210251.GD13061@ldl.fc.hp.com> <1250794594.2754.10.camel@sbs-t61.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1250794594.2754.10.camel@sbs-t61.sc.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Suresh Siddha : > On Wed, 2009-08-19 at 14:02 -0700, Alex Chiang wrote: > > I agree with you (although I thought that they should be > > 0-based) but this quirk addresses a specific platform, where > > I can assume certain things about the BIOS, etc. > > What happens if for some reason, newer bios/newer cpu > generations on this platform start having holes in the physical > id space? We can't rule out these kind of changes and we don't > want to go behind distros requesting fixes. > > > I agree with you in general, but again, this is a specific > > platform quirk where I have a good idea of what is a > > supported configuration. > > I am just nervous about future bios changes etc. Ok, let's separate the two conversations happening here. To me, the BIOS concerns are moot. I work closely with the BIOS engineers for this platform; I have knowledge of future plans for this BIOS and platform; and I know that they will not make any changes that break the assumptions in my patch. If they do, we will catch it during platform testing, file a bug, and not let them release their BIOS until it's fixed. Does that satisfy you? :) So the algorithm for mapping an APIC ID to a physical/chassis ID for this platform will not ever change. Now on the other hand, the /interface/ that we present to the user is the interesting conversation to have. > > > Easiest route will be to add a new entry in /proc/cpuinfo > > > > Well, if you remain unconvinced that fixing up 'physical id' is > > the proper thing to do, here are some alternate proposals: > > > > /proc/cpuinfo/chassis id > > /sys/devices/system/cpu/$cpu/chassis id > > /sys/devices/system/cpu/$cpu/topology/chassis id > > > > I really like this alternate proposal. This is simple and straight > forward to everyone. I am leaning towards sysfs, and prefer: /sys/devices/system/cpu/$cpu/chassis_id How does that sound? Thanks. /ac