From owner-freebsd-stable@FreeBSD.ORG Mon Feb 8 16:29:14 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CF28E1065695 for ; Mon, 8 Feb 2010 16:29:14 +0000 (UTC) (envelope-from freebsd-listen@fabiankeil.de) Received: from smtprelay02.ispgateway.de (smtprelay02.ispgateway.de [80.67.29.24]) by mx1.freebsd.org (Postfix) with ESMTP id 59FC28FC1C for ; Mon, 8 Feb 2010 16:29:14 +0000 (UTC) Received: from [87.79.193.4] (helo=r500.local) by smtprelay02.ispgateway.de with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.68) (envelope-from ) id 1NeWJ1-0002Ko-N9 for freebsd-stable@freebsd.org; Mon, 08 Feb 2010 17:17:47 +0100 Date: Mon, 8 Feb 2010 17:18:22 +0100 From: Fabian Keil To: freebsd-stable@freebsd.org Message-ID: <20100208171822.12773278@r500.local> In-Reply-To: <20100208145147.GA3733@icarus.home.lan> References: <20100208143329.GA12057@megatron.madpilot.net> <20100208145147.GA3733@icarus.home.lan> X-Mailer: Claws Mail 3.7.4 (GTK+ 2.18.6; amd64-portbld-freebsd9.0) X-PGP-KEY-URL: http://www.fabiankeil.de/gpg-keys/freebsd-listen-2008-08-18.asc Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/CV70vSwVb2oMLr7jxC3nJA4"; protocol="application/pgp-signature" X-Df-Sender: 775067 Subject: Re: ATA_CAM + ZFS gives short 1-2 seconds system freeze on disk load X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Feb 2010 16:29:14 -0000 --Sig_/CV70vSwVb2oMLr7jxC3nJA4 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Jeremy Chadwick wrote: > On Mon, Feb 08, 2010 at 03:33:29PM +0100, Guido Falsi wrote: > > I'm seeing this problem on my machine at work. It's an HP DC 7800, > > mounts an ich9 chipset(not ahci capable). I'm attaching the dmesg. > >=20 > > I noticed this in the past, but it got evident(and very annoying) > > while recompiling many ports today after the jpeg-8 update. > >=20 > > It looks like it freezes the system for the second or two it takes > > to flush buffers to disk when there are big outputs. This happens > > when decompressiong big distfiles, mainly. The openoffice port > > triggers this almost continuosly every few seconds during compilation. > > I've also seen this when working with big files(for example graphic > > images in uncompressed formats). > >=20 > > It gets very annoying and I don't remember this happening before > > activating the ATA_CAM flag. There was some slowdown with big disk > > access, but not a total freeze. >=20 > This happens without ATA_CAM (e.g. using ataahci(4) or any other > controller driver). Indeed. > The behaviour you're describing (bursty heavy disk I/O that stalls the > subsystem) is pretty much the norm on all FreeBSD systems I've seen with > ZFS. When it starts happening, it's easy to notice/follow using "zpool > iostat 1" or "gstat -I500ms". Lots of I/O will happen (read or write) > and the ARC is essentially being thrashed -- said utilities won't show > any I/O counters incrementing until some threshold is reached, where > you'll see a massive amount of I/O reported, during which time the > system is sluggish (beyond acceptable levels, IMHO). A few seconds > later, the I/O counters start reporting 0 as the ARC gets used, then > a few seconds massive I/O, rinse lather repeat. I experienced what I think is the same problem. ZFS's bulk disk flushes caused vlc to occasionally stutter when viewing a DVD rip from disk while ripping a DVD at the same time. My workaround is to put "vfs.zfs.txg.timeout=3D3" in /boot/loader.conf. I think I read about this on zfs-discuss@. I assume on faster systems one can use a higher value. I'm currently updating the jpeg dependencies, too: fk@r500 ~ $zpool iostat 1 capacity operations bandwidth pool used avail read write read write ---------- ----- ----- ----- ----- ----- ----- tank 176G 52.1G 22 40 1.40M 1.85M tank 176G 52.1G 73 0 9.24M 0 tank 176G 52.1G 73 0 9.05M 0 tank 176G 52.1G 42 176 5.12M 11.3M tank 176G 52.1G 68 0 8.62M 0 tank 176G 52.1G 67 0 8.43M 0 tank 176G 52.1G 57 106 7.11M 9.54M tank 176G 52.1G 75 0 9.50M 0 tank 176G 52.1G 76 0 9.62M 0 tank 176G 52.1G 46 167 5.74M 11.7M tank 176G 52.1G 79 0 9.99M 0 tank 176G 52.1G 81 0 10.2M 0 tank 176G 52.1G 43 164 5.43M 11.7M tank 176G 52.1G 71 0 9.00M 0 tank 176G 52.1G 61 39 7.74M 5.00M tank 176G 52.1G 46 111 5.74M 9.17M tank 176G 52.1G 71 0 8.99M 0 tank 176G 52.1G 80 0 10.1M 0 tank 176G 52.1G 47 113 5.87M 9.68M tank 176G 52.1G 70 0 8.87M 0 tank 176G 52.1G 78 0 9.80M 0 tank 176G 52.1G 42 164 5.24M 11.3M tank 176G 52.1G 76 0 9.62M 0 tank 176G 52.1G 79 0 9.99M 0 tank 176G 52.1G 49 153 6.11M 10.8M tank 176G 52.1G 72 0 9.12M 0 Fabian --Sig_/CV70vSwVb2oMLr7jxC3nJA4 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAktwOVcACgkQBYqIVf93VJ3u+QCgnudevzboYRjzkRajHNanpHWP 72wAoKiezne4xZRxYAsKdON8OqR6DnxR =t8D8 -----END PGP SIGNATURE----- --Sig_/CV70vSwVb2oMLr7jxC3nJA4--