From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] Re: [PATCH] virtio-blk: add SGI_IO passthru support
Date: Wed, 29 Apr 2009 12:11:19 +0100
Message-ID: <200904291211.20374.paul@codesourcery.com>
References: <20090427082606.GA32604@lst.de> <49F730AD.8090705@codemonkey.ws> <20090429104854.GA7846@lst.de>
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Cc: Christoph Hellwig <hch@lst.de>,
	Anthony Liguori <anthony@codemonkey.ws>, kvm@vger.kernel.org,
	Rusty Russell <rusty@rustcorp.com.au>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Hannes Reinecke <hare@suse.de>
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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?

I can maybe see that virtio-blk is slightly simpler for dumb drivers, though 
even then a basic scsi host is pretty straightforward and I find it hard to 
believe there's much real benefit.

Paul