Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757272AbYHMRkQ (ORCPT ); Wed, 13 Aug 2008 13:40:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756817AbYHMRjz (ORCPT ); Wed, 13 Aug 2008 13:39:55 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:36391 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756322AbYHMRjz (ORCPT ); Wed, 13 Aug 2008 13:39:55 -0400 Date: Wed, 13 Aug 2008 19:39:40 +0200 From: Ingo Molnar To: Jeff Chua Cc: Yinghai Lu , David Miller , Linux Kernel Subject: Re: 2.6.27rc1 cannot boot more than 8CPUs Message-ID: <20080813173940.GA32214@elte.hu> References: <20080813141629.GD19397@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1594 Lines: 42 * Jeff Chua wrote: > On Thu, Aug 14, 2008 at 1:10 AM, Jeff Chua wrote: > > On Wed, Aug 13, 2008 at 10:16 PM, Ingo Molnar wrote: > > > >> btw., could you please check that v2.6.27-rc3 (or later) kernels boot > >> fine (with about 8 cpus) even if you have genericarch/bigsmp disabled, > >> and do not silently hang as it happened on your box before? > > > > With 16 CPUs, it still hangs, but now the console is showing the > > errors as intended. > > ... but it is supposed to hang? > > I tried with just CONFIG_NR_CPUS=8 and this time it booted, but stange > thing is I only see 2 CPUs! To be more precise, it's without both > CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP. > > And when I tried to enable the CPUs, it complained about: > > # cat cpu6/online > 0 > # echo 1 > cpu6/online > More than 8 CPUs detected - skipping them. > Use CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP. > -bash: echo: write error: Input/output error > > Prior to the patch, the system booted with all 8 CPUs. > > Again, if I enable both CONFIG_X86_GENERICARCH and CONFIG_X86_BIGSMP, > I get all 16 CPUs. Yinghai, could the APIC ID enumeration be nonsequential and we skip CPUs starting at the third one already? I think we should accept all CPUs that are within our support range. Ingo -- 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/