From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262850AbVFWXed (ORCPT ); Thu, 23 Jun 2005 19:34:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262848AbVFWXeb (ORCPT ); Thu, 23 Jun 2005 19:34:31 -0400 Received: from mail13.syd.optusnet.com.au ([211.29.132.194]:48056 "EHLO mail13.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S262883AbVFWXeN (ORCPT ); Thu, 23 Jun 2005 19:34:13 -0400 From: Con Kolivas To: linux-kernel@vger.kernel.org, spaminos-ker@yahoo.com Subject: Re: cfq misbehaving on 2.6.11-1.14_FC3 Date: Fri, 24 Jun 2005 09:33:53 +1000 User-Agent: KMail/1.8.1 Cc: Jens Axboe , Andrew Morton References: <20050623183051.98655.qmail@web30710.mail.mud.yahoo.com> In-Reply-To: <20050623183051.98655.qmail@web30710.mail.mud.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1551494.juKB0KsZ6r"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200506240933.55951.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --nextPart1551494.juKB0KsZ6r Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Fri, 24 Jun 2005 04:30, spaminos-ker@yahoo.com wrote: > --- Jens Axboe wrote: > > Journalled file systems will behave worse for this, because it has to > > tend to the journal as well. Can you try mounting that partition as ext2 > > and see what numbers that gives you? > > I did the tests again on a partition that I could mkfs/mount at will. > > On ext3, I get about 33 seconds average latency. > > And on ext2, as predicted, I have latencies in average of about 0.4 > seconds. > > I also tried reiserfs, and it gets about 22 seconds latency. > > As you pointed out, it seems that there is a flow in the way IO queues and > journals (that are in some ways queues as well), interact in the presence > of flushes. I found the same, and the effect was blunted by noatime and=20 journal_data_writeback (on ext3). Try them one at a time and see what you=20 get. Cheers, Con --nextPart1551494.juKB0KsZ6r Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBCu0bjZUg7+tp6mRURAhPPAJ46XcrflO3LSn5xaAAszUFsSYPS/QCfULLf BS2wcpNz4XBAhdVdx/lAPZE= =rCyR -----END PGP SIGNATURE----- --nextPart1551494.juKB0KsZ6r--