From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753587Ab1K3NE2 (ORCPT ); Wed, 30 Nov 2011 08:04:28 -0500 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:60891 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751341Ab1K3NE0 (ORCPT ); Wed, 30 Nov 2011 08:04:26 -0500 Message-ID: <4ED629CB.401@linux.vnet.ibm.com> Date: Wed, 30 Nov 2011 14:04:11 +0100 From: Christian Ehrhardt User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.23) Gecko/20110921 Thunderbird/3.1.15 MIME-Version: 1.0 To: Wu Fengguang CC: Dave Chinner , Jan Kara , Christoph Hellwig , Andrew Morton , Linux Memory Management List , "linux-fsdevel@vger.kernel.org" , Ankit Jain , Rik van Riel , Nikanth Karthikesan , LKML , Andi Kleen Subject: Re: [PATCH 2/8] readahead: make default readahead size a kernel parameter References: <20111121091819.394895091@intel.com> <20111121093846.251104145@intel.com> <20111121100137.GC5084@infradead.org> <20111121113540.GB8895@localhost> <20111124222822.GG29519@quack.suse.cz> <20111125003633.GP2386@dastard> <20111128023922.GA2141@localhost> In-Reply-To: <20111128023922.GA2141@localhost> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit x-cbid: 11113013-0542-0000-0000-0000003B48EB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/28/2011 03:39 AM, Wu Fengguang wrote: > On Fri, Nov 25, 2011 at 08:36:33AM +0800, Dave Chinner wrote: >> On Thu, Nov 24, 2011 at 11:28:22PM +0100, Jan Kara wrote: >>> On Mon 21-11-11 19:35:40, Wu Fengguang wrote: >>>> On Mon, Nov 21, 2011 at 06:01:37PM +0800, Christoph Hellwig wrote: >>>>> On Mon, Nov 21, 2011 at 05:18:21PM +0800, Wu Fengguang wrote: >>>>>> From: Nikanth Karthikesan >>>>>> [...] >> >> And one that has already been in use for exactly this purpose for >> years. Indeed, it's far more flexible because you can give different >> types of devices different default readahead settings quite easily, >> and it you can set different defaults for just about any tunable >> parameter (e.g. readahead, ctq depth, max IO sizes, etc) in the same >> way. > > I'm interested in this usage, too. Would you share some of your rules? > FYI - This is an example of a rules Suse delivers in SLES @ s390 for a while now. With little modifications it could be used for all Dave mentioned above. cat /etc/udev/rules.d/60-readahead.rules # # Rules to set an increased default max readahead size for s390 disk devices # This file should be installed in /etc/udev/rules.d # SUBSYSTEM!="block", GOTO="ra_end" ACTION!="add", GOTO="ra_end" # on device add set initial readahead to 512 (instead of in kernel 128) KERNEL=="sd*[!0-9]", ATTR{queue/read_ahead_kb}="512" KERNEL=="dasd*[!0-9]", ATTR{queue/read_ahead_kb}="512" LABEL="ra_end" -- Grüsse / regards, Christian Ehrhardt IBM Linux Technology Center, System z Linux Performance