From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:48850)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <namei.unix@gmail.com>) id 1UD4xV-0008CB-CS
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 22:24:02 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <namei.unix@gmail.com>) id 1UD4xU-0002Vm-Cv
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 22:24:01 -0500
Received: from mail-pb0-f53.google.com ([209.85.160.53]:39757)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <namei.unix@gmail.com>) id 1UD4xU-0002Vg-64
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 22:24:00 -0500
Received: by mail-pb0-f53.google.com with SMTP id un1so5356834pbc.12
	for <qemu-devel@nongnu.org>; Tue, 05 Mar 2013 19:23:58 -0800 (PST)
Message-ID: <5136B6C4.7040509@gmail.com>
Date: Wed, 06 Mar 2013 11:23:48 +0800
From: Liu Yuan <namei.unix@gmail.com>
MIME-Version: 1.0
References: <20130305141845.GA3411@irqsave.net>
	<CAJSP0QXULZHuoPmZLSj33-Rh3r7FH+Hgho2FkD9qFJ+uwi2pJw@mail.gmail.com>
In-Reply-To: <CAJSP0QXULZHuoPmZLSj33-Rh3r7FH+Hgho2FkD9qFJ+uwi2pJw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] Dataplane and vhost-blk
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: Stefan Hajnoczi <stefanha@gmail.com>
Cc: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= <benoit.canet@irqsave.net>, qemu-devel <qemu-devel@nongnu.org>

On 03/05/2013 11:59 PM, Stefan Hajnoczi wrote:
>> I am looking for a way to help improving qemu block performance.
>> >
>> > APIC-V is a work in progress and the two options with public code are vhost-*
>> > and virtio-blk-dataplane.
>> >
>> > The way of doing seems very similar (bypassing the qemu lock) and dedicating
>> > a thread to each emulated virtio block device.
>> >
>> > vhost-* is in kernel while dataplane is in qemu.
> Yes, they take a similar approach.  The main difference is using a
> vhost kernel thread versus a QEMU userspace thread.
> 

The other merit of blk-dataplane over in-kernel vhost_blk that I can
think of, is underlying various protocols such as Sheepdog would benefit
from it without adding code, assuming the final goal of blk-dataplain is
fully fulfilled that aims to be integrated into QEMU block layer. For
vhost_blk, ony local backing file will benefit from it without adding
more code in the kernel.

Thanks,
Yuan