From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263020AbVFXDb4 (ORCPT ); Thu, 23 Jun 2005 23:31:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263024AbVFXD3j (ORCPT ); Thu, 23 Jun 2005 23:29:39 -0400 Received: from mail19.syd.optusnet.com.au ([211.29.132.200]:36813 "EHLO mail19.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S263029AbVFXD1y (ORCPT ); Thu, 23 Jun 2005 23:27:54 -0400 From: Con Kolivas To: spaminos-ker@yahoo.com Subject: Re: cfq misbehaving on 2.6.11-1.14_FC3 Date: Fri, 24 Jun 2005 13:27:28 +1000 User-Agent: KMail/1.8.1 Cc: linux-kernel@vger.kernel.org, Jens Axboe , Andrew Morton References: <20050624023356.63888.qmail@web30705.mail.mud.yahoo.com> In-Reply-To: <20050624023356.63888.qmail@web30705.mail.mud.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2063186.5mn2sRinXa"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200506241327.31043.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --nextPart2063186.5mn2sRinXa Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Fri, 24 Jun 2005 12:33, spaminos-ker@yahoo.com wrote: > --- Con Kolivas wrote: > > I found the same, and the effect was blunted by noatime and > > journal_data_writeback (on ext3). Try them one at a time and see what y= ou > > get. > > I had to move to a different box, but get the same kind of results (for > ext3 default mount options). > > Here are the latencies (all cfq) I get with different values for the mount > parameters > > ext2 default > 0.1s > > ext3 default > 52.6s avg > > reiser defaults > 29s avg 5 minutes > then, > 12.9s avg > > ext3 rw,noatime,data=3Dwriteback > 0.1s avg > > reiser rw,noatime,data=3Dwriteback > 4s avg for 20 seconds > then 0.1 seconds avg > > > So, indeed adding noatime,data=3Dwriteback to the mount options improves > things a lot. > I also tried without the noatime, and that doesn't make much difference to > me. > > That looks like a good workaround, I'll now try with the actual server and > see how things go. That's more or less what I found, although I found noatime also helped my t= est=20 cases, but also less than the journal options. Coincidentally I only=20 discovered this recently and hadn't gotten around to telling anyone how=20 dramatic this was and this seemed as good a time as any. I am suspicious th= at=20 it wasn't this bad in past kernels but haven't been able to instrument=20 earlier kernels to check. Cheers, Con --nextPart2063186.5mn2sRinXa Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBCu32jZUg7+tp6mRURAjqFAJ4tr7YKNG88xQE6xQnw7efyzz5UogCeMYUt uJlcD963LOcgu/PMKylFERg= =f5ke -----END PGP SIGNATURE----- --nextPart2063186.5mn2sRinXa--