Note to readers: This codebase is useful to get started with BFT consensus and as baseline when designing your own protocols. If you are looking for state-of-the-art BFT protocols, I recommend Tusk (asynchronous) and Bullshark (partially-synchronous) that provide superior performance, robustness, and scalability.

HotStuff

This repo provides a minimal implementation of the 2-chain variant of the HotStuff consensus protocol used at the core of Diem. The codebase has been designed to be small, efficient, and easy to benchmark and modify. It has not been designed to run in production but uses real cryptography (dalek), networking (tokio), and storage (rocksdb).

Quick Start

HotStuff is written in Rust, but all benchmarking scripts are written in Python and run with Fabric. To deploy and benchmark a testbed of 4 nodes on your local machine, clone the repo and install the python dependencies:

git clone https://github.com/asonnino/hotstuff.git
cd hotstuff/benchmark
pip install -r requirements.txt

You also need to install Clang (required by rocksdb) and tmux (which runs all nodes and clients in the background). Finally, run a local benchmark using fabric:

fab local

This command may take a long time the first time you run it (compiling rust code in release mode may be slow) and you can customize a number of benchmark parameters in fabfile.py. When the benchmark terminates, it displays a summary of the execution similarly to the one below.

-----------------------------------------
 SUMMARY:
-----------------------------------------
 + CONFIG:
 Faults: 0 nodes
 Committee size: 4 nodes
 Input rate: 1,000 tx/s
 Transaction size: 512 B
 Execution time: 20 s

 Consensus timeout delay: 1,000 ms
 Consensus sync retry delay: 10,000 ms
 Mempool GC depth: 50 rounds
 Mempool sync retry delay: 5,000 ms
 Mempool sync retry nodes: 3 nodes
 Mempool batch size: 15,000 B
 Mempool max batch delay: 10 ms

 + RESULTS:
 Consensus TPS: 967 tx/s
 Consensus BPS: 495,294 B/s
 Consensus latency: 2 ms

 End-to-end TPS: 960 tx/s
 End-to-end BPS: 491,519 B/s
 End-to-end latency: 9 ms
-----------------------------------------

Next Steps

The wiki documents the codebase, explains its architecture and how to read benchmarks' results, and provides a step-by-step tutorial to run benchmarks on Amazon Web Services across multiple data centers (WAN).

License

This software is licensed as Apache 2.0.