From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992578AbXEBAro (ORCPT ); Tue, 1 May 2007 20:47:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992581AbXEBAro (ORCPT ); Tue, 1 May 2007 20:47:44 -0400 Received: from accolon.hansenpartnership.com ([64.109.89.108]:39327 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992578AbXEBArn (ORCPT ); Tue, 1 May 2007 20:47:43 -0400 Subject: Re: [PATCH] fix dynticks for voyager From: James Bottomley To: Jeremy Fitzhardinge Cc: Matt Mackall , Thomas Gleixner , linux-kernel In-Reply-To: <4637DA9F.3030503@goop.org> References: <1177951131.3674.37.camel@mulgrave.il.steeleye.com> <20070501222432.GP11166@waste.org> <4637DA9F.3030503@goop.org> Content-Type: text/plain Date: Tue, 01 May 2007 19:47:39 -0500 Message-Id: <1178066859.4320.90.camel@mulgrave.il.steeleye.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2007-05-01 at 17:26 -0700, Jeremy Fitzhardinge wrote: > Matt Mackall wrote: > > On Mon, Apr 30, 2007 at 11:38:51AM -0500, James Bottomley wrote: > > > >> As usual voyager tripped over an explicit boot CPU is zero assumption in > >> the dynticks code. This is the fix I have queued in the voyager tree. > >> > > > > Can we flush out all these assumptions by adding a constant offset > > somewhere? Or reversing the ordering? It might be useful to voyager, but unless the offset were random, people would simply hardwire it. > My understanding is that the boot CPU is random depending on who wins > the "I get to boot" bunfight. Not quite. On apic systems, the boot CPU can be an arbitrary physical id but is conventionally logical id 0. On voyager, the CPU id actually maps to a fixed location, so there's no sense in having a logical id. The booting CPU on voyager is simply the lowest numbered CPU that comes up through the SUS boot. James