From: Eric Sandeen Subject: delalloc is crippling fs_mark performance Date: Fri, 18 Jul 2008 11:11:30 -0500 Message-ID: <4880C0B2.9040706@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: ext4 development Return-path: Received: from mx1.redhat.com ([66.187.233.31]:40733 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750758AbYGRQLc (ORCPT ); Fri, 18 Jul 2008 12:11:32 -0400 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id m6IGBVTs025484 for ; Fri, 18 Jul 2008 12:11:31 -0400 Received: from pobox-2.corp.redhat.com (pobox-2.corp.redhat.com [10.11.255.15]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m6IGBVhv011229 for ; Fri, 18 Jul 2008 12:11:31 -0400 Received: from Liberator.local (sebastian-int.corp.redhat.com [172.16.52.221]) by pobox-2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m6IGBUMS023024 for ; Fri, 18 Jul 2008 12:11:30 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: running fs_mark like this: fs_mark -d /mnt/test -D 256 -n 100000 -t 4 -s 20480 -F -S 0 (256 subdirs, 100000 files/iteration, 4 threads, 20k files, no sync) on a 1T fs, with and without delalloc (mount option), is pretty interesting: http://people.redhat.com/esandeen/ext4/fs_mark.png somehow delalloc is crushing performance here. I'm planning to wait 'til the fs is full and see what the effect is on fsck, and look at the directory layout for differences compared to w/o delalloc. But something seems to have gone awry here ... This is on 2.6.26 with the patch queue applied up to stable. -Eric