io_uring and AF_XDP

Status Draft outlineSection Networking and I/O

These are different mechanisms. io_uring is an asynchronous kernel I/O interface; it does not generally bypass the kernel. AF_XDP exposes a fast packet path through XDP and shared rings while retaining kernel participation. DPDK’s poll-mode drivers are the book’s primary example of userspace NIC access that bypasses the ordinary kernel network stack.

Planned model

Compare conventional sockets, io_uring, AF_XDP, and DPDK. Show submissions, completions, copies, wake-ups, ownership, setup cost, and which kernel work remains in each path.

Questions

• Which kernel work remains in each path?
• Who owns a registered buffer at every instant?
• When does operational complexity outweigh saved overhead?

Exercise

Draw the lifecycle of one receive buffer from NIC arrival through application processing and safe reuse.