Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] Re: [PATCH v2 00/16] Vhost-pci for inter-VM communication

["Wang, Wei W" <wei.w.wang@intel.com>]

On Monday, May 22, 2017 10:28 AM, Jason Wang wrote:
> On 2017年05月19日 23:33, Stefan Hajnoczi wrote:
> > On Fri, May 19, 2017 at 11:10:33AM +0800, Jason Wang wrote:
> >> On 2017年05月18日 11:03, Wei Wang wrote:
> >>> On 05/17/2017 02:22 PM, Jason Wang wrote:
> >>>> On 2017年05月17日 14:16, Jason Wang wrote:
> >>>>> On 2017年05月16日 15:12, Wei Wang wrote:
> >>>>>>> Hi:
> >>>>>>>
> >>>>>>> Care to post the driver codes too?
> >>>>>>>
> >>>>>> OK. It may take some time to clean up the driver code before post
> >>>>>> it out. You can first have a check of the draft at the repo here:
> >>>>>> https://github.com/wei-w-wang/vhost-pci-driver
> >>>>>>
> >>>>>> Best,
> >>>>>> Wei
> >>>>> Interesting, looks like there's one copy on tx side. We used to
> >>>>> have zerocopy support for tun for VM2VM traffic. Could you please
> >>>>> try to compare it with your vhost-pci-net by:
> >>>>>
> >>> We can analyze from the whole data path - from VM1's network stack
> >>> to send packets -> VM2's network stack to receive packets. The
> >>> number of copies are actually the same for both.
> >> That's why I'm asking you to compare the performance. The only reason
> >> for vhost-pci is performance. You should prove it.
> > There is another reason for vhost-pci besides maximum performance:
> >
> > vhost-pci makes it possible for end-users to run networking or storage
> > appliances in compute clouds.  Cloud providers do not allow end-users
> > to run custom vhost-user processes on the host so you need vhost-pci.
> >
> > Stefan
> 
> Then it has non NFV use cases and the question goes back to the performance
> comparing between vhost-pci and zerocopy vhost_net. If it does not perform
> better, it was less interesting at least in this case.
> 

Probably I can share what we got about vhost-pci and vhost-user:
https://github.com/wei-w-wang/vhost-pci-discussion/blob/master/vhost_pci_vs_vhost_user.pdf
Right now, I don’t have the environment to add the vhost_net test.

Btw, do you have data about vhost_net v.s. vhost_user?

Best,
Wei