From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263743AbUHWLrm (ORCPT ); Mon, 23 Aug 2004 07:47:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263733AbUHWLrl (ORCPT ); Mon, 23 Aug 2004 07:47:41 -0400 Received: from [213.188.213.77] ([213.188.213.77]:44755 "EHLO server1.navynet.it") by vger.kernel.org with ESMTP id S263640AbUHWLql (ORCPT ); Mon, 23 Aug 2004 07:46:41 -0400 From: "Massimo Cetra" To: "'Nick Piggin'" Cc: Subject: RE: Production comparison between 2.4.27 and 2.6.8.1 Date: Mon, 23 Aug 2004 13:46:33 +0200 Message-ID: <000001c48906$d70bf270$0600640a@guendalin> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2627 In-Reply-To: <4127F7FD.5060804@yahoo.com.au> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nick Piggin wrote: > > #********************************************** > > It is my first experience with 2.6 branch kernels, because > i am trying > > to figure out if the tree is performing well to switch > everithing in > > production, so my ideas may be wrong... > > > > Raid tests may be faked because of the overhead caused by > md sync (and > > probably raid is better on 2.6). However it seems that libsata has > > better performance on 2.4 (hdparm) xfs tests shows that 2.4 > has better > > performance if compared to 2.6 and the difference, in my > opinion, is > > not linked on libsata better performance. > > > > What is your opinion ? > > What can I try to improve performance ? > > > > I wouldn't worry too much about hdparm measurements. If you > want to test the streaming throughput of the disk, run dd > if=big-file of=/dev/null or a large write+sync. > > Regarding your worse non-RAID XFS database results, try > booting 2.6 with elevator=deadline and test again. If yes, > are you using queueing (TCQ) on your disks? Tried even with 2.6.8.1-mm and 2.6.8.1-ck No performance improvement. >>From Documentation/block/as-iosched.txt i read: #-------------------------------------- Attention! Database servers, especially those using "TCQ" disks should investigate performance with the 'deadline' IO scheduler. Any system with high disk performance requirements should do so, in fact. If you see unusual performance characteristics of your disk systems, or you see big performance regressions versus the deadline scheduler, please email me. Database users don't bother unless you're willing to test a lot of patches from me ;) its a known issue. #-------------------------------------- So it's probably known that 2.6 performance with databases and heavy HD access is an issue. I don't believe that 2.6.x tree is performing as well as 2.4.x(-lck) on server tasks. Is this issue being analyzed ? Should we hope in an improvement sometime? Or I'll have to use 2.4 to have good performance ? Max