From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:35035)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1a3oHD-00044y-4L
	for qemu-devel@nongnu.org; Tue, 01 Dec 2015 11:59:43 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1a3oH8-00026l-P8
	for qemu-devel@nongnu.org; Tue, 01 Dec 2015 11:59:39 -0500
Received: from mx4-phx2.redhat.com ([209.132.183.25]:52793)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1a3oH8-00026g-Go
	for qemu-devel@nongnu.org; Tue, 01 Dec 2015 11:59:34 -0500
Date: Tue, 1 Dec 2015 11:59:06 -0500 (EST)
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <998355860.30506151.1448989146641.JavaMail.zimbra@redhat.com>
In-Reply-To: <1448987171.3041.2.camel@hasee>
References: <1447978868-17138-1-git-send-email-mlin@kernel.org>
	<56506D95.70101@redhat.com> <1448266667.18175.5.camel@hasee>
	<56531F5F.3050709@redhat.com> <1448925639.27669.7.camel@ssi>
	<565DC48B.6030903@redhat.com> <1448987171.3041.2.camel@hasee>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [RFC PATCH 0/9] vhost-nvme: new qemu nvme backend
 using nvme target
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Ming Lin <mlin@kernel.org>
Cc: qemu-devel@nongnu.org, Christoph Hellwig <hch@lst.de>, linux-nvme@lists.infradead.org, virtualization@lists.linux-foundation.org


> What do you think about virtio-nvme+vhost-nvme?

What would be the advantage over virtio-blk?  Multiqueue is not supported
by QEMU but it's already supported by Linux (commit 6a27b656fc).

To me, the advantage of nvme is that it provides more than decent performance on
unmodified Windows guests, and thanks to your vendor extension can be used
on Linux as well with speeds comparable to virtio-blk.  So it's potentially
a very good choice for a cloud provider that wants to support Windows guests
(together with e.g. a fast SAS emulated controller to replace virtio-scsi,
and emulated igb or ixgbe to replace virtio-net).

Which features are supported by NVMe and not virtio-blk?

Paolo

> I also have patch for vritio-nvme:
> https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=nvme-split/virtio
> 
> Just need to change vhost-nvme to work with it.
> 
> > 
> > Paolo
> > 
> > > Still tuning.
> 
> 
>