From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755444AbZHTVUZ (ORCPT ); Thu, 20 Aug 2009 17:20:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754400AbZHTVUY (ORCPT ); Thu, 20 Aug 2009 17:20:24 -0400 Received: from g1t0028.austin.hp.com ([15.216.28.35]:31648 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752204AbZHTVUY (ORCPT ); Thu, 20 Aug 2009 17:20:24 -0400 Date: Thu, 20 Aug 2009 15:20:24 -0600 From: Alex Chiang To: Andi Kleen Cc: Suresh Siddha , "hpa@zytor.com" , "mingo@redhat.com" , "tglx@linutronix.de" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: add /proc/cpuinfo/physical id quirks Message-ID: <20090820212024.GG13061@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> <20090820205425.GF13061@ldl.fc.hp.com> <20090820210342.GC29994@basil.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090820210342.GC29994@basil.fritz.box> 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 * Andi Kleen : > > I am leaning towards sysfs, and prefer: > > > > /sys/devices/system/cpu/$cpu/chassis_id > > > > How does that sound? > > I would prefer to simply use the existing physical id for this > like in your original patch. We already have a bewildering zoo > of different CPU IDs, no need to increase the confusion even > more. This was my initial instinct as well, and was why I was trying to find out the original intent of "physical id". It seemed unambiguous to me, but I was trying to figure out what history (if any) there was around its semantics. Since "physical id" is basically a made-up field (i.e., isn't represented directly in cpuid instruction), it does seem like the appropriate place for any quirky platforms to hook into if necessary. > Incidentially mcelog already knows how to use physical ID for this, > would need to be changed for a new sysfs interface There is probably a lot of userspace stuff that looks at physical id that would need to be taught about a new interface. It turns out I need to rework my patch anyway because I need to think about the case where a user disables some cores in the BIOS, in which case my (fragile) table selection scheme falls apart. But I would like to get some agreement/guidance about how we end up presenting the information to the user. Thanks. /ac