Re: [RFC Optimizing veth xsk performance 00/10]

[Paolo Abeni]

On Thu, 2023-08-03 at 22:04 +0800, huangjie.albert wrote:
> AF_XDP is a kernel bypass technology that can greatly improve performance.
> However, for virtual devices like veth, even with the use of AF_XDP sockets,
> there are still many additional software paths that consume CPU resources. 
> This patch series focuses on optimizing the performance of AF_XDP sockets 
> for veth virtual devices. Patches 1 to 4 mainly involve preparatory work. 
> Patch 5 introduces tx queue and tx napi for packet transmission, while 
> patch 9 primarily implements zero-copy, and patch 10 adds support for 
> batch sending of IPv4 UDP packets. These optimizations significantly reduce 
> the software path and support checksum offload.
> 
> I tested those feature with
> A typical topology is shown below:
> veth<-->veth-peer                                    veth1-peer<--->veth1
> 	1       |                                                  |   7
> 	        |2                                                6|
> 	        |                                                  |
> 	      bridge<------->eth0(mlnx5)- switch -eth1(mlnx5)<--->bridge1
>                   3                    4                 5    
>              (machine1)                              (machine2)    
> AF_XDP socket is attach to veth and veth1. and send packets to physical NIC(eth0)
> veth:(172.17.0.2/24)
> bridge:(172.17.0.1/24)
> eth0:(192.168.156.66/24)
> 
> eth1(172.17.0.2/24)
> bridge1:(172.17.0.1/24)
> eth0:(192.168.156.88/24)
> 
> after set default route��?snat��?dnat. we can have a tests
> to get the performance results.
> 
> packets send from veth to veth1:
> af_xdp test tool:
> link:https://github.com/cclinuxer/libxudp
> send:(veth)
> ./objs/xudpperf send --dst 192.168.156.88:6002 -l 1300
> recv:(veth1)
> ./objs/xudpperf recv --src 172.17.0.2:6002
> 
> udp test tool:iperf3
> send:(veth)
> iperf3 -c 192.168.156.88 -p 6002 -l 1300 -b 60G -u

Should be: '-b 0' otherwise you will experience additional overhead.

And you would likely pin processes and irqs to ensure BH and US run on
different cores of the same numa node.

Cheers,

Paolo