From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751309AbcFRIY3 (ORCPT ); Sat, 18 Jun 2016 04:24:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44337 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750977AbcFRIY0 (ORCPT ); Sat, 18 Jun 2016 04:24:26 -0400 Date: Sat, 18 Jun 2016 16:24:22 +0800 From: Baoquan He To: tglx@linutronix.de Cc: linux-kernel@vger.kernel.org Subject: The difference between x86_cpu_to_apicid and x86_bios_cpu_apicid Message-ID: <20160618082422.GA4065@x1.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Sat, 18 Jun 2016 08:24:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, Sorry to bother you. I am always wondering what's the difference between x86_cpu_to_apicid and x86_bios_cpu_apicid. Or in other words, I don't know why x86_bios_cpu_apicid is required. From code both x86_cpu_to_apicid and x86_bios_cpu_apicid stores the apicid correspond to a certain logic cpu number. With my understanding x86_cpu_to_apicid can do what x86_bios_cpu_apicid is doing except for its usage in below commit. commit 1f12e32f4cd5243ae46d8b933181be0d022c6793 Author: Thomas Gleixner Date: Mon Feb 22 22:19:15 2016 +0000 x86/topology: Create logical package id Could you please help to explain when it's convenient to you? Thanks Baoquan