XDPerf

xdperf logo

Inspiration

Many network performance testing tools depend on DPDK (Data Plane Development Kit), which requires complex setup and strict hardware requirements. Additionally, existing tools like Trex are Python-based, making dependency management cumbersome.

xdperf was born from the desire to create "a high-performance traffic generator that works without DPDK, runs as a single binary, and can flexibly generate arbitrary packets."

What it does

xdperf is a high-performance network traffic generation tool that leverages XDP (eXpress Data Path).

Client/Server modes: Supports send-only, receive-only, and bidirectional measurements
WASM plugin system: Define arbitrary packet formats through plugins
High throughput: Achieves millions of pps through XDP kernel bypass
PPS control: Rate limiting with target pps (packets per second)
Statistics: Real-time send/receive statistics and NIC-level statistics display

How we built it

Architecture:

eBPF/XDP layer (C): The xdp_tx program reads packet templates from eBPF maps and transmits directly via XDP_TX
Control layer (Go): Loads and manages BPF programs using the cilium/ebpf library, and includes a template generator that takes the desired packets and processing logic as input to produce the packet to be injected.
Plugin layer (TinyGo and Go →WASM): Executes packet generation logic on the wazero runtime

Challenges we ran into

Fighting the BPF Verifier: Code optimizations like loop unrolling and bounds checking were necessary to pass the BPF verifier
Supporting both TinyGo and Go as WASM plugins: Ensuring that both TinyGo-compiled and Go-compiled WASM modules run reliably on wazero was particularly difficult.Differences in runtime behavior, memory model, and build constraints required substantial engineering effort.
Per-CPU map design: Managing packet indices during parallel execution across multiple CPUs required a design where each CPU maintains independent state
Packet size adjustment: Handling edge cases when dynamically changing packet size with bpf_xdp_adjust_tail()

Accomplishments that we're proud of

DPDK-free: Works without special drivers or hardware configuration
- Single binary: Easy deployment thanks to Go implementation
- Plugin extensibility: Safe and flexible packet generation through WASM
- Client/Server modes: Supports bidirectional network measurement
Designed the Template feature that provides a clean boundary between plugins and the host

What we learned

How XDP works: High-speed path that bypasses the kernel network stack
eBPF programming: Map operations, verifier constraints, per-CPU variable handling
WASM hosting: Executing WASM modules within Go using wazero
gopacket: Low-level packet construction in Go