Re: [Qemu-devel] Dataplane and vhost-blk

[Liu Yuan <namei.unix@gmail.com>]

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