High-Performance Networking Using eBPF, XDP, and io_uring
In the networking world there are a number of ways to increase performance over naive use of basic Berkeley sockets. These techniques have ranged from polling blocking sockets, non-blocking sockets controlled by Epoll, all the way through completely bypassing the Linux kernel for maximum network performance where you talk directly to the network interface card by using something like DPDK or Netmap. All these tools have their place, and generally occupy a space from convenience to performance. But in recent years, that landscape has changed massively.. The tools available to the average Linux systems developer have improved from the creation of io_uring, to the expansion of bpf from a simple filtering language to a full-on programming environment embedded directly in the kernel. Along with that came something called XDP (express datapath). This was Linux kernel's answer to kernel-bypass networking. AF_XDP is the new socket type created by this feature, and generally works very similarly to something like DPDK. History lessons out of the way, this talk will look into, and discuss the merits of this technology, it's place in the broader ecosystem and how it can be used to attain the highest level of performance possible. This talk dives into crucial details, such as how AF_XDP works, how it can be integrated into a larger system and finally more advanced topics such as request sharding/load balancing. There is a detailed look at the design of AF_XDP, the eBpf code used, as well as the userspace code required to drive it all. It also includes performance numbers from this setup compared to regular kernel networking. And most importantly how to put all this together to handle as much data as possible on a single modern multi-core system.