From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032032AbWLGLFP (ORCPT ); Thu, 7 Dec 2006 06:05:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1032033AbWLGLFO (ORCPT ); Thu, 7 Dec 2006 06:05:14 -0500 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:46918 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1032032AbWLGLFM (ORCPT ); Thu, 7 Dec 2006 06:05:12 -0500 Date: Thu, 7 Dec 2006 11:07:37 +0000 From: Alan To: Bob Cc: linux-kernel@vger.kernel.org Subject: Re: Kernel 2.6 SMP very slow with ServerWorks LE Chipset Message-ID: <20061207110737.6c506c98@localhost.localdomain> In-Reply-To: <4577AA11.6020906@homeurl.co.uk> References: <4577AA11.6020906@homeurl.co.uk> X-Mailer: Sylpheed-Claws 2.6.0 (GTK+ 2.8.20; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > As a test of raw CPU power I've been decompressing the kernel tree, with > a UP 2.6 kernel this takes about 1m 15s, I don't know if bz2 is > multithreaded but even if it's not I would expect a slight speed increase > but in fact with a SMP 2.6 kernel it take 13 ~ 26m, with a SMP 2.4 > kernel it takes 1m 28s and with a 2.4 UP 1m 35s. The 2.4 numbers look correct (slightly slower), the 2.6 numbers do not. Nothing obviously wrong from the traces however. If you pin the bzip to a given processor do you get different results according to which CPU ? (see man taskset for info on the commands) If you get very different times on the two processors that will be very useful information.