From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751434Ab0EPXgW (ORCPT ); Sun, 16 May 2010 19:36:22 -0400 Received: from www.tglx.de ([62.245.132.106]:57648 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142Ab0EPXgU (ORCPT ); Sun, 16 May 2010 19:36:20 -0400 Date: Mon, 17 May 2010 01:36:06 +0200 (CEST) From: Thomas Gleixner To: Donald Allen cc: john stultz , LKML , Arjan van de Ven Subject: Re: PROBLEM: tickless scheduling In-Reply-To: Message-ID: References: <1273540344.3843.101.camel@localhost.localdomain> <1273697523.2856.3.camel@localhost.localdomain> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) 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 Donald, On Sat, 15 May 2010, Donald Allen wrote: > Attached. This is from the 2.6.30 kernel on the Arch Linux install cd. > > Here's another bit of data. As I've said previously, the problems I'm > reporting were observed on a Toshiba NB310-305 netbook with a > single-core Atom 450 processor. I just built myself a mini-ITX system > using the Intel D510MO motherboard, which provides a dual-core D510 > Atom processor. The other hardware on the board is similar to the > Toshiba. I installed the same Slackware snapshot I used on the > Toshiba, and did the home directory transfer without any problem at > all with the default tickless kernel. The hardware isn't identical, > and while I don't know the internals of the Linux kernel at all, my > gut, backed up by many years of OS development work in scheduling and > memory management, is telling me that the key difference is dual- vs. > single-core. Just a guess. I fear you are wrong. The key difference is almost certainly that the BIOS of your netbook tries to be overly clever vs. power management and is not aware of the fact that the Linux kernel uses timer hardware in a very different way than the other OS which comes preinstalled on that machine. The overly clever BIOS power management which works nicely with the vendor provided "drivers" for the other OS is just interfering with the kernels way of dealing with the problem. Can you please boot with "hpet=disable" on the kernel command line ? Thanks, tglx