From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762281AbXGFKMB (ORCPT ); Fri, 6 Jul 2007 06:12:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758000AbXGFKLy (ORCPT ); Fri, 6 Jul 2007 06:11:54 -0400 Received: from web32604.mail.mud.yahoo.com ([68.142.207.231]:33092 "HELO web32604.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755300AbXGFKLx (ORCPT ); Fri, 6 Jul 2007 06:11:53 -0400 X-YMail-OSG: qFav5.IVM1mG2nP.cYcVjB5OMhCOIzQUmGGh0Xr_zwetrqc4mDGbhT60qKoRLGq3uhYV2cUTLX7reKigPDgTY8q7cQ-- X-RocketYMMF: knobi.rm Date: Fri, 6 Jul 2007 03:11:53 -0700 (PDT) From: Martin Knoblauch Reply-To: spamtrap@knobisoft.de Subject: Re: Understanding I/O behaviour To: Robert Hancock Cc: linux-kernel@vger.kernel.org In-Reply-To: <468D832B.4060002@shaw.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Message-ID: <197707.68164.qm@web32604.mail.mud.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --- Robert Hancock wrote: > > Try playing with reducing /proc/sys/vm/dirty_ratio and see how that > helps. This workload will fill up memory with dirty data very > quickly, > and it seems like system responsiveness often goes down the toilet > when > this happens and the system is going crazy trying to write it all > out. > Definitely the "going crazy" part is the worst problem I see with 2.6 based kernels (late 2.4 was really better in this corner case). I am just now playing with dirty_ratio. Anybody knows what the lower limit is? "0" seems acceptabel, but does it actually imply "write out immediatelly"? Another problem, the VM parameters are not really well dociúmented in their behaviour and interdependence. Cheers Martin ------------------------------------------------------ Martin Knoblauch email: k n o b i AT knobisoft DOT de www: http://www.knobisoft.de