From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH] fs: sync: fixed performance regression Date: Thu, 11 Jul 2013 12:00:12 +1000 Message-ID: <20130711020012.GA5652@dastard> References: <1373497956-8770-1-git-send-email-taysom@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, jack@suse.cz, sonnyrao@chromium.org To: Paul Taysom Return-path: Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:61066 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754922Ab3GKCAQ (ORCPT ); Wed, 10 Jul 2013 22:00:16 -0400 Content-Disposition: inline In-Reply-To: <1373497956-8770-1-git-send-email-taysom@chromium.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Jul 10, 2013 at 04:12:36PM -0700, Paul Taysom wrote: > The following commit introduced a 10x regression for > syncing inodes in ext4 with relatime enabled where just > the atime had been modified. > > commit 4ea425b63a3dfeb7707fc7cc7161c11a51e871ed > Author: Jan Kara > Date: Tue Jul 3 16:45:34 2012 +0200 > vfs: Avoid unnecessary WB_SYNC_NONE writeback during sys_sync and reorder sync passes > > See also: http://www.kernelhub.org/?msg=93100&p=2 > > Fixed by putting back in the call to writeback_inodes_sb. > > I'll attach the test in a reply to this e-mail. > > The test starts by creating 512 files, syncing, reading one byte > from each of those files, syncing, and then deleting each file > and syncing. The time to do each sync is printed. The process > is then repeated for 1024 files and then the next power of > two up to 262144 files. > > Note, when running the test, the slow down doesn't always happen > but most of the tests will show a slow down. Can you please check if the patch attached to this mail: http://marc.info/?l=linux-kernel&m=137276874025813&w=2 Fixes your problem? Cheers, Dave. -- Dave Chinner david@fromorbit.com