On 12/14/2018 07:00 PM, Stefan Hajnoczi wrote:
> On Thu, Dec 13, 2018 at 12:22 AM Nikos Dragazis
> <ndragazis(a)outlook.com.gr> wrote:
>> These are all solved by a special virtio device called
>> “virtio-vhost-user”. This device was created by Stefan Hajnoczi and is
>> described here:
>> https://wiki.qemu.org/Features/VirtioVhostUser
> Hi Nikos,
> Nice that you're pushing virtio-vhost-user.  I'm focussed on other
> projects and probably won't resume virtio-vhost-user work any time
> soon.  It was done as part of the vhost-pci effort that Wei Wang from
> Intel was pursuing, so I've CCed them.
>
> Although virtio-vhost-user may have been stalled, I still think it's a
> good solution for device emulation inside VMs.
>
> With some effort virtio-vhost-user can get upstream into the VIRTIO
> specification, QEMU, and SPDK.  A starting point would be to resend
> the VIRTIO spec, QEMU, SPDK patches.  The VIRTIO spec is here:
> https://stefanha.github.io/virtio/vhost-user-slave.html#x1-2830007
>
> If I remember correctly, most of the remaining work was in SPDK/DPDK,
> where the vhost-user library may need refactoring.  I have CCed
> Dariusz, who was working on a general rte_vhost library overhaul and
> had already looked at virtio-vhost-user.
>

It seems Nikos wasn't included in the email, have him cc-ed

Agree with Stefan that virtio-vhost-user is a good inter-VM 
communication solution.
With the previous Vhost-PCI PoC, the 2 VM networking communication (64B 
packet)
throughput is around 1.6x larger than the exiting OVS based solution. 
The data path of
virtio-vhost-user remains the same as Vhost-PCI, so we would also expect 
it to have a
similar good performance.

Btw, could you guys share your usage of this inter-VM communication 
solution in the
storage domain?

Best,
Wei