From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754547Ab0ETNr7 (ORCPT ); Thu, 20 May 2010 09:47:59 -0400 Received: from lon1-post-3.mail.demon.net ([195.173.77.150]:51457 "EHLO lon1-post-3.mail.demon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753102Ab0ETNr6 (ORCPT ); Thu, 20 May 2010 09:47:58 -0400 Message-ID: <4BF53D8B.5090407@rsk.demon.co.uk> Date: Thu, 20 May 2010 14:47:55 +0100 From: Richard Kennedy User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Heinz Diehl CC: linux-kernel@vger.kernel.org, linux-mm , lwoodman@redhat.com Subject: Re: RFC: dirty_ratio back to 40% References: <4BF51B0A.1050901@redhat.com> <20100520122919.GA3420@fancy-poultry.org> In-Reply-To: <20100520122919.GA3420@fancy-poultry.org> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/05/10 13:29, Heinz Diehl wrote: > On 20.05.2010, Larry Woodman wrote: > lwoodman@redhat.com >> Increasing the dirty_ratio to 40% will regain the performance loss seen >> in several benchmarks. Whats everyone think about this??? > > These are tuneable via sysctl. What I have in my /etc/sysctl.conf is > > vm.dirty_ratio = 4 > vm.dirty_background_ratio = 2 > > This writes back the data more often and frequently, thus preventing the > system from long stalls. > > Works at least for me. AMD Quadcore, 8 GB RAM. > get_dirty_limits uses a minimum vm_dirty_ratio of 5, so you can't set it lower than that (unless you use vm_dirty_bytes). But it's interesting that you find lowering the dirty_ratio helpful. Do you have any benchmark results you can share? regards Richard