From: Andreas Dilger Subject: Re: HUGE slowdown when doing dpkg with ext4 over nbd Date: Tue, 6 Dec 2016 11:45:16 -0700 Message-ID: <78AEFE7B-685B-4B4E-A15E-E3F6D99DD343@dilger.ca> References: <1621417488.8583313.1481030030711.JavaMail.zimbra@online.net> Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Content-Type: multipart/signed; boundary="Apple-Mail=_750E623C-1211-47E5-9FF4-A2579E4EC0EA"; protocol="application/pgp-signature"; micalg=pgp-sha256 Cc: linux-ext4@vger.kernel.org To: Renaud Mariana Return-path: Received: from mail-io0-f178.google.com ([209.85.223.178]:35627 "EHLO mail-io0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751581AbcLFSqh (ORCPT ); Tue, 6 Dec 2016 13:46:37 -0500 Received: by mail-io0-f178.google.com with SMTP id a124so668695984ioe.2 for ; Tue, 06 Dec 2016 10:45:20 -0800 (PST) In-Reply-To: <1621417488.8583313.1481030030711.JavaMail.zimbra@online.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: --Apple-Mail=_750E623C-1211-47E5-9FF4-A2579E4EC0EA Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On Dec 6, 2016, at 6:13 AM, Renaud Mariana wrote: >=20 > Hello, >=20 > We have noticed a HUGE slowdown when doing dpkg with ext4 over nbd = (qemu-nbd as a server) >=20 > dpkg times with default mkfs & mount options is : >=20 > - ext4: 10 mn > - xfs : 30s. >=20 > Disabling extents : > mkfs.ext4 -O ^extent > fixed the pb that is ext4 is as fast as xfs. >=20 > Any ideas ? Is dpkg using fallocate() (uninitialized extents)? Could you strace the = dpkg process with -fff to catch forked processes and search for fallocate() = calls. fallocate() is the only thing I can think of that would make extents = slower than block-mapped files. > Details : >=20 > xnbd-client --blocksize 4096 qemu-nbd-ip 10000 /dev/nbd0 > mkfs.ext4 /dev/nbd0 > mount /dev/nbd0 /newroot >=20 > wget https://download.elastic.co/kibana/kibana/kibana-4.6.1-amd64.deb > time dpkg -i kibana-4.6.1-amd64.deb What kernel version are you currently running? Is this problem new with this kernel (i.e. it worked fine with older = kernels? > kibana installs many small files (23209 entries) under /opt/kibana How small are the files? Cheers, Andreas --Apple-Mail=_750E623C-1211-47E5-9FF4-A2579E4EC0EA Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iQIVAwUBWEcHPHKl2rkXzB/gAQgsog//bNoXy+kxPM5209xBh+GEwHe+gTnclAky UmrpAO+w7mthy+v/qcHF8JMSYoi/+Mu9qArt/RrGXWjd+jVaG0QF1GRB66sn7Hf9 G7c2B3uXv1ZlcTwLYdWIy6YtTftToZx3/znfPdhz+57M7dsqlfpdJeOpjmV0S1gA SA920X9gMAoN//CJUoQzGO2S9CL1+u/3iPpzIv5I+ZBZub6TkWhc27CeqU3noQqk /USW/yz1L2tqm36ttgT0oa8nOX1v6QgC/osK1B9Hps41XE06/JE2sFyN7CZu6Wb6 Dik5n77A2sRLIBlvWNAB/BXetXSeOKckc16zdQooKbpPCPSTHr9r8v/rdKPCPFlE Imgle3i0ECB5SPEg38jcSx+8d1fhKIItpnSD7QsJKzYrs6h2L7qvCxAHL+a3VNaU BjnxEfTPOdrdqIvhZS2ysmWLO+yHVAXY7S9TICAcO1EdJdqDdjgdR+9ZESC6/xhZ izWBSwZKmdmHKsp1/hC9H3F3vwin+x467znBqJpRVYKeoTb4CDYz0wIbTXER+90F ICBjxoHRCBu6CrYCQysKWnRXq6EKxYFRmbAfamLA9iHhLHt64dfW+5TkTaeXIoQR RKiW8HJp0Ervhz87hbYIji0jbuStoAD4r14xCnknfNKRAehcDvxs1jHyI6ChDGga R6Gj/4dU20c= =URbD -----END PGP SIGNATURE----- --Apple-Mail=_750E623C-1211-47E5-9FF4-A2579E4EC0EA--