Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752700Ab0A3RSO (ORCPT ); Sat, 30 Jan 2010 12:18:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751745Ab0A3RSN (ORCPT ); Sat, 30 Jan 2010 12:18:13 -0500 Received: from mail-ew0-f228.google.com ([209.85.219.228]:32771 "EHLO mail-ew0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209Ab0A3RSK (ORCPT ); Sat, 30 Jan 2010 12:18:10 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; b=uAD3LlIDVdG5aniuVubawWzwhZChnyY2HbGyJqgNMFgTbpcYAZxT2OxwVnt8l+FvT3 f4dymKBFxPWNjk2Jf8sRb5wD7oHfMT5KkZq3PeBK9L4I5XzuPfE1pSGPMGq0oR5C9unW auK7AjR7McpoHhwo/2hDCQhTHVRTqUXWKH42g= Date: Sat, 30 Jan 2010 18:18:04 +0100 From: Borislav Petkov To: zhiyi Cc: linux-kernel@vger.kernel.org, Zhiyi Huang Subject: Re: nr_cpu_ids incorrect on AMD Quad-Core Opteron 8380 Message-ID: <20100130171804.GA2348@liondog.tnic> Mail-Followup-To: Borislav Petkov , zhiyi , linux-kernel@vger.kernel.org, Zhiyi Huang References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1194 Lines: 27 On Thu, Jan 28, 2010 at 12:16:44PM +1300, zhiyi wrote: > Hi, > I have just found the value of nr_cpu_ids is 32, instead of 16 on my > new Dell PowerEdge R905 which has 16 cpus (4 quad-core Opteron > 8380). However, /proc/cpuinfo displays the right number (16). > I have searched the archive but found no related subject. Is there > any patch already available to fix the problem? > I am using 2.6.31-4 and verified this incorrect value (32) using a > module. nr_cpu_ids is set to CONFIG_NR_CPUS on SMP kernels and denotes the max CPUs supported by your kernel. This is not a bug but a configurable option in the kernel for saving memory. You can still set CONFIG_NR_CPUS in "-> Processor type and features" to the max number of cores N you have on your machine if you want to save approx 8*N KB. But guessing from your quadsocket configuration, memory shouldn't be that scarce on that machine to go the trouble :). -- Regards/Gruss, Boris. -- 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/