From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754932AbYAIPZ7 (ORCPT ); Wed, 9 Jan 2008 10:25:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752010AbYAIPZw (ORCPT ); Wed, 9 Jan 2008 10:25:52 -0500 Received: from ns2.suse.de ([195.135.220.15]:39033 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751420AbYAIPZw (ORCPT ); Wed, 9 Jan 2008 10:25:52 -0500 To: VUB Stefan Seidel Cc: linux-kernel@vger.kernel.org Subject: Re: Not all logical processors activated on Dual Core Xeon (== no Hyperthreading) From: Andi Kleen References: <47849240.3040305@vub.de> Date: Wed, 09 Jan 2008 16:25:50 +0100 In-Reply-To: <47849240.3040305@vub.de> (VUB Stefan Seidel's message of "Wed\, 09 Jan 2008 10\:22\:08 +0100") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org VUB Stefan Seidel writes: > I have the following system here: two dual-core Xeon 5130 on an Intel > S5000V-SA motherboard. The kernel detects 4 CPUs, from what I learn > through /proc/cpuinfo, these are the 4 cores (two per > package). However, I think it should be 8 logical processors, because > the Xeons should be able to do Hyperthreading (or Core2 Duo based Xeons do not support Hyper Threading. > =========================== > but acpidump shows 8 CPUs in multiple locations: That's likely because the BIOS supports Quad Core CPUs, but does not disable the excessive objects if you only plug in Dual Core -Andi