From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264549AbTL0Tyz (ORCPT ); Sat, 27 Dec 2003 14:54:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264557AbTL0Tyz (ORCPT ); Sat, 27 Dec 2003 14:54:55 -0500 Received: from fep01.swip.net ([130.244.199.129]:9467 "EHLO fep01-svc.swip.net") by vger.kernel.org with ESMTP id S264549AbTL0Tyx (ORCPT ); Sat, 27 Dec 2003 14:54:53 -0500 Message-ID: <3FEDE389.4090103@free.fr> Date: Sat, 27 Dec 2003 20:54:49 +0100 From: Jean-Luc Fontaine User-Agent: Mozilla/5.0 (X11; U; Linux i586; en-US; rv:1.6b) Gecko/20031210 X-Accept-Language: en-us, ja MIME-Version: 1.0 To: Kernel Mailing List CC: Linus Torvalds , Jens Axboe Subject: Re: IDE performance drop between 2.4.23 and 2.6.0 References: <3FED9A87.4020209@free.fr> In-Reply-To: X-Enigmail-Version: 0.82.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Linus Torvalds wrote: | | On Sat, 27 Dec 2003, Jean-Luc Fontaine wrote: | |>I solved the problem in a very strange way. Note that the (b) disk |>performance only improves after readahead has been increased on another |>(c) drive! (the (c) drive performance was also increased by to 2.4 |>levels but is not shown here). I could reliably repeat this behavior |>after rebooting. |> |>Can any IDE expert explain it? | | | Looks like a bug. If you don't access hdc, hdc is / for 2.6, whereas hdb is used for 2.4. So hdc was obviously accessed prior to this test. | then the read-ahead on hdc | shouldn't matter. I wonder if the read-ahead code (either the setting or | the reading) gets the value from the wrong queue or something. Or could this set something in the VIA chipset? I'll take a look in /proc/ide/via and report if needed. Let me know if you need more tests to be run. - -- Jean-Luc Fontaine mailto:jfontain@free.fr http://jfontain.free.fr/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQE/7eOIkG/MMvcT1qQRAjAxAKCr3xDbqELBzY7zsOYCQi/7QsYw7ACeObup auyEo8bDPNHOD79+/I8/xPw= =rsrt -----END PGP SIGNATURE-----