From: Gerd Hoffmann <kraxel@redhat.com>
To: qemu-devel@nongnu.org
Cc: Chris Wright <chrisw@redhat.com>,
Mark McLoughlin <markmc@redhat.com>,
Ryan Harper <ryanh@us.ibm.com>,
Laurent Vivier <Laurent.Vivier@bull.net>,
kvm-devel <kvm-devel@lists.sourceforge.net>
Subject: Re: [Qemu-devel] [RFC] Disk integrity in QEMU
Date: Fri, 10 Oct 2008 09:54:14 +0200 [thread overview]
Message-ID: <48EF0A26.90209@redhat.com> (raw)
In-Reply-To: <48EE38B9.2050106@codemonkey.ws>
Hi,
> Read performance should be unaffected by using O_DSYNC. O_DIRECT will
> significantly reduce read performance. I think we should use O_DSYNC by
> default and I have sent out a patch that contains that. We will follow
> up with benchmarks to demonstrate this.
So O_SYNC on/off is pretty much equivalent to disk write caching being
on/off, right? So we could make that guest-controlled, i.e. toggeling
write caching in the guest (using hdparm) toggles O_SYNC in qemu? This
together with disk-flush command support (mapping to fsync on the host)
should allow guests to go into barrier mode for better write performance
without loosing data integrity.
cheers,
Gerd
next prev parent reply other threads:[~2008-10-10 7:55 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-09 17:00 [Qemu-devel] [RFC] Disk integrity in QEMU Anthony Liguori
2008-10-10 7:54 ` Gerd Hoffmann [this message]
2008-10-10 8:12 ` Mark McLoughlin
2008-10-12 23:10 ` Jamie Lokier
2008-10-14 17:15 ` Avi Kivity
2008-10-10 9:32 ` Avi Kivity
2008-10-12 23:00 ` Jamie Lokier
2008-10-10 8:11 ` Aurelien Jarno
2008-10-10 12:26 ` Anthony Liguori
2008-10-10 12:53 ` Paul Brook
2008-10-10 13:55 ` Anthony Liguori
2008-10-10 14:05 ` Paul Brook
2008-10-10 14:19 ` Avi Kivity
2008-10-17 13:14 ` Jens Axboe
2008-10-19 9:13 ` Avi Kivity
2008-10-10 15:48 ` Aurelien Jarno
2008-10-10 9:16 ` Avi Kivity
2008-10-10 9:58 ` Daniel P. Berrange
2008-10-10 10:26 ` Avi Kivity
2008-10-10 12:59 ` Paul Brook
2008-10-10 13:20 ` Avi Kivity
2008-10-10 12:34 ` Anthony Liguori
2008-10-10 12:56 ` Avi Kivity
2008-10-11 9:07 ` andrzej zaborowski
2008-10-11 17:54 ` Mark Wagner
2008-10-11 20:35 ` Anthony Liguori
2008-10-12 0:43 ` Mark Wagner
2008-10-12 1:50 ` Chris Wright
2008-10-12 16:22 ` Jamie Lokier
2008-10-12 17:54 ` Anthony Liguori
2008-10-12 18:14 ` nuitari-qemu
2008-10-13 0:27 ` Mark Wagner
2008-10-13 1:21 ` Anthony Liguori
2008-10-13 2:09 ` Mark Wagner
2008-10-13 3:16 ` Anthony Liguori
2008-10-13 6:42 ` Aurelien Jarno
2008-10-13 14:38 ` Steve Ofsthun
2008-10-12 0:44 ` Chris Wright
2008-10-12 10:21 ` Avi Kivity
2008-10-12 14:37 ` Dor Laor
2008-10-12 15:35 ` Jamie Lokier
2008-10-12 18:00 ` Anthony Liguori
2008-10-12 18:02 ` Anthony Liguori
2008-10-15 10:17 ` Andrea Arcangeli
2008-10-12 17:59 ` Anthony Liguori
2008-10-12 18:34 ` Avi Kivity
2008-10-12 19:33 ` Izik Eidus
2008-10-14 17:08 ` Avi Kivity
2008-10-12 19:59 ` Anthony Liguori
2008-10-12 20:43 ` Avi Kivity
2008-10-12 21:11 ` Anthony Liguori
2008-10-14 15:21 ` Avi Kivity
2008-10-14 15:32 ` Anthony Liguori
2008-10-14 15:43 ` Avi Kivity
2008-10-14 19:25 ` Laurent Vivier
2008-10-16 9:47 ` Avi Kivity
2008-10-12 10:12 ` Avi Kivity
2008-10-17 13:20 ` Jens Axboe
2008-10-19 9:01 ` Avi Kivity
2008-10-19 18:10 ` Jens Axboe
2008-10-19 18:23 ` Avi Kivity
2008-10-19 19:17 ` M. Warner Losh
2008-10-19 19:31 ` Avi Kivity
2008-10-19 18:24 ` Avi Kivity
2008-10-19 18:36 ` Jens Axboe
2008-10-19 19:11 ` Avi Kivity
2008-10-19 19:30 ` Jens Axboe
2008-10-19 20:16 ` Avi Kivity
2008-10-20 14:14 ` Avi Kivity
2008-10-10 10:03 ` Fabrice Bellard
2008-10-13 16:11 ` Laurent Vivier
2008-10-13 16:58 ` Anthony Liguori
2008-10-13 17:36 ` Jamie Lokier
2008-10-13 17:06 ` [Qemu-devel] " Ryan Harper
2008-10-13 18:43 ` Anthony Liguori
2008-10-14 16:42 ` Avi Kivity
2008-10-13 18:51 ` Laurent Vivier
2008-10-13 19:43 ` Ryan Harper
2008-10-13 20:21 ` Laurent Vivier
2008-10-13 21:05 ` Ryan Harper
2008-10-15 13:10 ` Laurent Vivier
2008-10-16 10:24 ` Laurent Vivier
2008-10-16 13:43 ` Anthony Liguori
2008-10-16 16:08 ` Laurent Vivier
2008-10-17 12:48 ` Avi Kivity
2008-10-17 13:17 ` Laurent Vivier
2008-10-14 10:05 ` Kevin Wolf
2008-10-14 14:32 ` Ryan Harper
2008-10-14 16:37 ` Avi Kivity
2008-10-13 19:00 ` Mark Wagner
2008-10-13 19:15 ` Ryan Harper
2008-10-14 16:49 ` Avi Kivity
2008-10-13 17:58 ` [Qemu-devel] " Rik van Riel
2008-10-13 18:22 ` Jamie Lokier
2008-10-13 18:34 ` Rik van Riel
2008-10-14 1:56 ` Jamie Lokier
2008-10-14 2:28 ` nuitari-qemu
2008-10-28 17:34 ` Ian Jackson
2008-10-28 17:45 ` Anthony Liguori
2008-10-28 17:50 ` Ian Jackson
2008-10-28 18:19 ` Jamie Lokier
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