From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joris Subject: ICH7: ata_piix twice as fast as ahci? Date: Sun, 17 Feb 2008 16:41:42 +0100 Message-ID: <6b9952490802170741h1de9be53nefccea3775f7de00@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from an-out-0708.google.com ([209.85.132.248]:55255 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001AbYBQPln (ORCPT ); Sun, 17 Feb 2008 10:41:43 -0500 Received: by an-out-0708.google.com with SMTP id d31so305895and.103 for ; Sun, 17 Feb 2008 07:41:43 -0800 (PST) Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Linux IDE Hello List, Odd problem on my machines: the sata disks appear to be a lot slower when used via ata_piix vs the ahci driver. * dd if=/dev/sda of=/dev/null runs at roughly 50MB/s under ahci a steady 100MB/s under ata_piix, same for hdparm * bonnie++ -d /home/bonnietest -s 16G -r 8192 -u root returns: ** ahci 64bit,16G,70460,99,92676,15,45442,6,66155,94,103556,7,515.9,0,16,4300,16,+++++,+++,2698,9,4735,18,+++++,+++,2611,9 ** ata_piix 32bit,16G,50939,99,88159,16,41311,11,38945,69,108351,16,352.9,0,16,5045,5,+++++,+++,3882,4,5099,5,+++++,+++,3489,3 Is this a known issue? Is there a way to diagnose and/or fix this? I'd love to combine a high-speed system with hotpluggable disks. Kind regards, Joris Extra info: I tried the following without result: * The 'raid' functionality was disabled in the bios. * Update kernels (the debian stable 2.6.18-6-amd64 and 2.6.22-3-amd64 from backports.org) * Reinstall OS in 32 bit mode * Limit the amount of ram on the machine to 2GB using the mem=2048M kernel parameter. HW info: Xeon 3210, Supermicro PDSMi+ motherboard, Seagate ES2 500GB sata disks, 8GB ram Sata controller: 00:1f.2 SATA controller: Intel Corporation 82801GR/GH (ICH7 Family) Serial ATA Storage Controller AHCI (rev 01) OS: A bare Debian 4.0 with all security updates, running nothing but some idle daemons and ssh.