From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753877Ab1BCV6R (ORCPT ); Thu, 3 Feb 2011 16:58:17 -0500 Received: from mvp.visionpro.com ([63.91.95.19]:50741 "EHLO extern.visionpro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751857Ab1BCV6Q (ORCPT ); Thu, 3 Feb 2011 16:58:16 -0500 User-Agent: Microsoft-Entourage/12.28.0.101117 Date: Thu, 03 Feb 2011 13:58:08 -0800 Subject: Re: Memset very slow From: "Brian D. McGrew" To: Alan Cox CC: Message-ID: Thread-Topic: Memset very slow Thread-Index: AcvD7XD13KVxtl3JakOj6K6KweEb3g== In-Reply-To: <20110203213158.62baa54c@lxorguk.ukuu.org.uk> Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit X-OriginalArrivalTime: 03 Feb 2011 21:58:08.0463 (UTC) FILETIME=[713C3DF0:01CBC3ED] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/3/11 1:31 PM, "Alan Cox" wrote: >> So, my question is, can someone explain to me what is going on here? I am >> not convinced this is a kernel problem just because a new kernel fixed it; >> but, if there were changes related to this in the kernel, then what is the >> oldest version I should be looking at to fix my issues? > > The newer kernel does several things that may be relevant - the obvious > one is that it rewrites and corrects MTRR data if it doesn't like what > the BIOS handed out. That would fit with dramatic slowdowns in memory > performance being fixed. The Dell precsion-linux mailing list almost immediately pointed me here: https://bugzilla.redhat.com/show_bug.cgi?id=581933 Which seems like it is my problem and the fix seems to work for me. -brian