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From: Christoph Hellwig <hch@infradead.org>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	"jaxboe@fusionio.com" <jaxboe@fusionio.com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>,
	"konrad@kernel.org" <konrad@kernel.org>
Subject: Re: [Xen-devel] Re: [PATCH v3] xen block backend.
Date: Thu, 21 Apr 2011 04:04:12 -0400	[thread overview]
Message-ID: <20110421080411.GA8969@infradead.org> (raw)
In-Reply-To: <1303370925.5997.322.camel@zakaz.uk.xensource.com>

On Thu, Apr 21, 2011 at 08:28:45AM +0100, Ian Campbell wrote:
> On Thu, 2011-04-21 at 04:37 +0100, Christoph Hellwig wrote:
> > This should sit in userspace.  And last time was discussed the issue
> > Stefano said the qemu Xen disk backend is just as fast as this kernel
> > code.  And that's with an not even very optimized codebase yet.
> 
> Stefano was comparing qdisk to blktap. This patch is blkback which is a
> completely in-kernel driver which exports raw block devices to guests,
> e.g. it's very useful in conjunction with LVM, iSCSI, etc. The last
> measurements I heard was that qdisk was around 15% down compared to
> blkback.

Please show real numbers on why adding this to kernel space is required.

  parent reply	other threads:[~2011-04-21  8:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-20 21:05 [PATCH v3] xen block backend Konrad Rzeszutek Wilk
2011-04-20 21:05 ` [PATCH] xen block backend driver Konrad Rzeszutek Wilk
2011-04-21  3:40   ` Christoph Hellwig
2011-04-21 19:03     ` [Xen-devel] " Daniel Stodden
2011-04-21 19:06       ` Christoph Hellwig
2011-04-21 19:14         ` [Xen-devel] " Daniel Stodden
2011-04-22  9:09           ` Christoph Hellwig
2011-05-02 19:08             ` [Xen-devel] Re: [PATCH] xen block backend driver. - proper flush/barrier/fua support missing Konrad Rzeszutek Wilk
2011-04-21  3:37 ` [PATCH v3] xen block backend Christoph Hellwig
2011-04-21  7:28   ` [Xen-devel] " Ian Campbell
2011-04-21  8:03     ` Ian Campbell
2011-04-21  8:06       ` Christoph Hellwig
2011-04-21  8:38         ` Ian Campbell
2011-04-21  8:04     ` Christoph Hellwig [this message]
2011-04-27 22:06       ` [Xen-devel] " Konrad Rzeszutek Wilk
2011-04-28 19:29         ` Pasi Kärkkäinen

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