From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266753AbUHaGo7 (ORCPT ); Tue, 31 Aug 2004 02:44:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266833AbUHaGo7 (ORCPT ); Tue, 31 Aug 2004 02:44:59 -0400 Received: from fw.osdl.org ([65.172.181.6]:18063 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S266753AbUHaGot (ORCPT ); Tue, 31 Aug 2004 02:44:49 -0400 Date: Mon, 30 Aug 2004 23:39:14 -0700 From: Andrew Morton To: Ram Pai Cc: nickpiggin@yahoo.com.au, hugh@veritas.com, dice@mfa.kfki.hu, vda@port.imtp.ilyichevsk.odessa.ua, linux-kernel@vger.kernel.org Subject: Re: data loss in 2.6.9-rc1-mm1 Message-Id: <20040830233914.0734fdd6.akpm@osdl.org> In-Reply-To: <1093933516.2424.55.camel@dyn319181.beaverton.ibm.com> References: <413131A0.4070100@yahoo.com.au> <1093933516.2424.55.camel@dyn319181.beaverton.ibm.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ram Pai wrote: > > > OK - maybe that can go for a spin in the next -mm. Andrew did you > > get it? > > So in case my vote counts, add my vote too :) . > Can someone send me the patch? > > But the biggest performance boost has been seen with large max-readahead > window sizes. Currently most of the underlying block devices default to > 32 pages max-readahead even though the underlying device can handle > much larger reads. We could extract much more sequential read > performance if the max-readahead was set to much higher values like 256 > pages which most modern devices are capable off. The problem AFAICT is > that the block device layer defaults the max-readahead value for most > block devices to 32, without consulting the capability of the underlying > block device driver. This can be done in startup scripts.