From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266181AbUBCXiW (ORCPT ); Tue, 3 Feb 2004 18:38:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266215AbUBCXiW (ORCPT ); Tue, 3 Feb 2004 18:38:22 -0500 Received: from gotroot.insekure.com ([207.254.222.218]:64264 "EHLO speedy.insekure.com") by vger.kernel.org with ESMTP id S266181AbUBCXiM (ORCPT ); Tue, 3 Feb 2004 18:38:12 -0500 Date: Tue, 3 Feb 2004 17:45:25 -0600 (CST) From: James Schmidt X-X-Sender: james@speedy.insekure.com To: linux-kernel@vger.kernel.org Subject: Re: broken maxcpus in 2.4.24 In-Reply-To: <1075765034.17943.79.camel@reactor.us.proofpoint.com> Message-ID: <20040203150930.W17910@speedy.insekure.com> References: <1075765034.17943.79.camel@reactor.us.proofpoint.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hope this hasn't been posted already. Not sure if I am right or not on this but this seems to be related, at least on my box, to the APIC IDs of the CPUs. I am using an Intel SE7500CW, populated with 2x XEONs. The APIC ID's of the CPUs are 0 & 1 for the first physical CPU, and 6 & 7 for the second physical CPU (don't ask me why). If I don't use NR_CPUs = 8, I don't seem to see the second physical CPU. Someone correct me if I'm wrong. -James On Mon, 2 Feb 2004, Dan Christian wrote: > I compiled a vanilla 2.4.24 for a 2 processor Xeon. > > I set CONFIG_NR_CPUS to 4 (2 CPUs x 2 hyperthreads each). > > When I boot the kernel, /proc/cpuinfo only shows 2 cpus (0-1) and > performance is bad. > > I reconfigure CONFIG_NR_CPUS back to 32. Now it shows 4 cpus (0-3) and > performance is normal. > > Is this a bug or am misunderstanding how to set this configuration > variable? > > -Dan Christian >