[PATCH 0/5] VSOCK: support mergeable rx buffer in vhost-vsock

Jason Wang
Tue, 06 Nov 2018 02:41:24 -0000

On 2018/11/6 ??10:17, jiangyiwen wrote:
> On 2018/11/5 17:21, Jason Wang wrote:
>> On 2018/11/5 ??3:43, jiangyiwen wrote:
>>> Now vsock only support send/receive small packet, it can't
achieve
>>> high performance. As previous discussed with Jason Wang, I revisit
the
>>> idea of vhost-net about mergeable rx buffer and implement the
mergeable
>>> rx buffer in vhost-vsock, it can allow big packet to be scattered
in
>>> into different buffers and improve performance obviously.
>>>
>>> I write a tool to test the vhost-vsock performance, mainly send big
>>> packet(64K) included guest->Host and Host->Guest. The result
as
>>> follows:
>>>
>>> Before performance:
>>>                 Single socket            Multiple sockets(Max
Bandwidth)
>>> Guest->Host   ~400MB/s                 ~480MB/s
>>> Host->Guest   ~1450MB/s                ~1600MB/s
>>>
>>> After performance:
>>>                 Single socket            Multiple sockets(Max
Bandwidth)
>>> Guest->Host   ~1700MB/s                ~2900MB/s
>>> Host->Guest   ~1700MB/s                ~2900MB/s
>>>
>>>   From the test results, the performance is improved obviously, and
guest
>>> memory will not be wasted.
>> Hi:
>>
>> Thanks for the patches and the numbers are really impressive.
>>
>> But instead of duplicating codes between sock and net. I was
considering to use virtio-net as a transport of vsock. Then we may have all
existed features likes batching, mergeable rx buffers and multiqueue. Want to
consider this idea? Thoughts?
>>
>>
> Hi Jason,
>
> I am not very familiar with virtio-net, so I am afraid I can't give too
> much effective advice. Then I have several problems:
>
> 1. If use virtio-net as a transport, guest should see a virtio-net
> device instead of virtio-vsock device, right? Is vsock only as a
> transport between socket and net_device? User should still use
> AF_VSOCK type to create socket, right?


Well, there're many choices. What you need is just to keep the socket
API and hide the implementation. For example, you can keep the vosck
device in guest and switch to use vhost-net in host. We probably need a
new feature bit or header to let vhost know we are passing vsock packet.
And vhost-net could forward the packet to vsock core on host.


>
> 2. I want to know if this idea has already started, and how is
> the current progress?


Not yet started.? Just want to listen from the community. If this sounds
good, do you have interest in implementing this?


>
> 3. And what is stefan's idea?


Talk with Stefan a little on this during KVM Forum. I think he tends to
agree on this idea. Anyway, let's wait for his reply.


Thanks


>
> Thanks,
> Yiwen.
>