From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91633C433E1 for ; Tue, 25 Aug 2020 19:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F6372074D for ; Tue, 25 Aug 2020 19:47:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZZkb0ejq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726542AbgHYTrf (ORCPT ); Tue, 25 Aug 2020 15:47:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:37306 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbgHYTre (ORCPT ); Tue, 25 Aug 2020 15:47:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598384853; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kpNcf7z1kt5bCNe5xLbtO4jyioxa3rzabBYBmt8aO2c=; b=ZZkb0ejqL3yIYpzXCOGbb7Ld49JISNUS5Num/Y8N7IkjJnSxo56/eJgwqDWOdyffWP4ZbZ C/GoefXOfurD096MwidNyt+INGHv7Hjc8jBiEJlUNJUUM4GUOQy2rhNt3Fxd7mi3WYm44f GBa7+kcYH8HJq+IlrJyIM5PvhbrsTj8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-34-PrCzxna_NCSqLNv5WZdDWw-1; Tue, 25 Aug 2020 15:47:30 -0400 X-MC-Unique: PrCzxna_NCSqLNv5WZdDWw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7C4EAF6C0C; Tue, 25 Aug 2020 19:47:27 +0000 (UTC) Received: from bfoster (ovpn-112-11.rdu2.redhat.com [10.10.112.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 77B1B6198E; Tue, 25 Aug 2020 19:47:26 +0000 (UTC) Date: Tue, 25 Aug 2020 15:47:24 -0400 From: Brian Foster To: Alberto Garcia Cc: Dave Chinner , Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , linux-xfs@vger.kernel.org Subject: Re: [PATCH 0/1] qcow2: Skip copy-on-write when allocating a zero cluster Message-ID: <20200825194724.GA338144@bfoster> References: <20200819175300.GA141399@bfoster> <20200820215811.GC7941@dread.disaster.area> <20200821110506.GB212879@bfoster> <20200821170232.GA220086@bfoster> <20200825165415.GB321765@bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Aug 25, 2020 at 07:18:19PM +0200, Alberto Garcia wrote: > On Tue 25 Aug 2020 06:54:15 PM CEST, Brian Foster wrote: > > If I compare this 5m fio test between XFS and ext4 on a couple of my > > systems (with either no prealloc or full file prealloc), I end up seeing > > ext4 run slightly faster on my vm and XFS slightly faster on bare metal. > > Either way, I don't see that huge disparity where ext4 is 5-6 times > > faster than XFS. Can you describe the test, filesystem and storage in > > detail where you observe such a discrepancy? > > Here's the test: > > fio --filename=/path/to/file.raw --direct=1 --randrepeat=1 \ > --eta=always --ioengine=libaio --iodepth=32 --numjobs=1 \ > --name=test --size=25G --io_limit=25G --ramp_time=0 \ > --rw=randwrite --bs=4k --runtime=300 --time_based=1 > My fio fallocates the entire file by default with this command. Is that the intent of this particular test? I added --fallocate=none to my test runs to incorporate the allocation cost in the I/Os. > The size of the XFS filesystem is 126 GB and it's almost empty, here's > the xfs_info output: > > meta-data=/dev/vg/test isize=512 agcount=4, agsize=8248576 > blks > = sectsz=512 attr=2, projid32bit=1 > = crc=1 finobt=1, sparse=1, > rmapbt=0 > = reflink=0 > data = bsize=4096 blocks=32994304, imaxpct=25 > = sunit=0 swidth=0 blks > naming =version 2 bsize=4096 ascii-ci=0, ftype=1 > log =internal log bsize=4096 blocks=16110, version=2 > = sectsz=512 sunit=0 blks, lazy-count=1 > realtime =none extsz=4096 blocks=0, rtextents=0 > > The size of the ext4 filesystem is 99GB, of which 49GB are free (that > is, without the file used in this test). The filesystem uses 4KB > blocks, a 128M journal and these features: > > Filesystem revision #: 1 (dynamic) > Filesystem features: has_journal ext_attr resize_inode dir_index > filetype needs_recovery extent flex_bg > sparse_super large_file huge_file uninit_bg > dir_nlink extra_isize > Filesystem flags: signed_directory_hash > Default mount options: user_xattr acl > > In both cases I'm using LVM on top of LUKS and the hard drive is a > Samsung SSD 850 PRO 1TB. > > The Linux version is 4.19.132-1 from Debian. > Thanks. I don't have LUKS in the mix on my box, but I was running on a more recent kernel (Fedora 5.7.15-100). I threw v4.19 on the box and saw a bit more of a delta between XFS (~14k iops) and ext4 (~24k). The same test shows ~17k iops for XFS and ~19k iops for ext4 on v5.7. If I increase the size of the LVM volume from 126G to >1TB, ext4 runs at roughly the same rate and XFS closes the gap to around ~19k iops as well. I'm not sure what might have changed since v4.19, but care to see if this is still an issue on a more recent kernel? Brian > Berto >