From: Paul Brook <paul@codesourcery.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: kvm@vger.kernel.org, Rusty Russell <rusty@rustcorp.com.au>,
qemu-devel@nongnu.org, Hannes Reinecke <hare@suse.de>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] Re: [PATCH] virtio-blk: add SGI_IO passthru support
Date: Wed, 29 Apr 2009 12:29:58 +0100 [thread overview]
Message-ID: <200904291229.59766.paul@codesourcery.com> (raw)
In-Reply-To: <200904291319.05247.borntraeger@de.ibm.com>
On Wednesday 29 April 2009, Christian Borntraeger wrote:
> Am Wednesday 29 April 2009 13:11:19 schrieb Paul Brook:
> > On Wednesday 29 April 2009, Christoph Hellwig wrote:
> > > On Tue, Apr 28, 2009 at 11:37:01AM -0500, Anthony Liguori wrote:
> > > > Ah, excellent. I think that's a great thing to do. So do you think
> > > > virtio-scsi would deprecate virtio-blk?
> > >
> > > I don't think so. If you have an image format or a non-scsi
> > > blockdevice underneath virtio-block avoids the encoding into SCSI CDBs
> > > and back and should be faster.
> >
> > Is this actually measurably faster, or just infinitesimally faster in
> > theory?
>
> If the underlying backing is 4k block size and the emulated scsi disk has
> 512 byte block size, write performance can be a lot slower.
Rubbish. If this is really a problem you can just use a scsi disk with 4k
sectors.
Paul
next prev parent reply other threads:[~2009-04-29 11:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090427082606.GA32604@lst.de>
2009-04-27 8:29 ` [Qemu-devel] [PATCH] virtio-blk: add SGI_IO passthru support Christoph Hellwig
2009-04-27 9:15 ` Avi Kivity
2009-04-28 9:47 ` Christoph Hellwig
2009-04-27 14:36 ` [Qemu-devel] " Anthony Liguori
2009-04-28 9:51 ` Christoph Hellwig
2009-04-28 16:37 ` Anthony Liguori
2009-04-28 16:52 ` Christian Borntraeger
2009-04-29 10:48 ` Christoph Hellwig
2009-04-29 11:11 ` Paul Brook
2009-04-29 11:19 ` Christian Borntraeger
2009-04-29 11:29 ` Paul Brook [this message]
2009-04-29 11:21 ` Christoph Hellwig
2009-04-29 11:37 ` Paul Brook
2009-04-30 20:13 ` Christoph Hellwig
2009-04-30 20:55 ` Nicholas A. Bellinger
2009-04-30 21:49 ` Paul Brook
2009-04-30 21:56 ` Javier Guerra
2009-05-01 7:24 ` Christoph Hellwig
2009-05-01 11:08 ` Jamie Lokier
2009-05-01 14:28 ` Christoph Hellwig
2009-05-05 5:21 ` Rusty Russell
2009-04-28 19:09 ` Christian Borntraeger
2009-04-29 10:50 ` Christoph Hellwig
2009-04-29 11:07 ` Christian Borntraeger
2009-04-28 9:57 ` [Qemu-devel] [PATCH 2/2] virtio-blk: add SG_IO " Christoph Hellwig
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