Note to readers: This codebase is built from a minimal implementation of the 2-chain variant of the HotStuff consensus protocol by asonnino.

SuperHotStuff

This repo tries to improve the throughput and latency of HotStuff by imposing an arbitrary topology to the mempool. This idea is motivated by the fact that broadcasting a batch of transactions to every peer is not scalable and very costly. Nodes which receive the block will relay it according to the topology. Three different topologies are implemented. :

• fullmesh : The broadcaster will send the block to every other nodes.
• kauri : The topology is a balanced n-ary tree where the broadcaster is the root.
• binomial : The topology is a binomial tree.

Note that we don't use a custom topology to relay consensus messages as we suppose that these messages are light and therefore are not a bottleneck.

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

SuperHotStuff 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
-----------------------------------------

TODO :

• Signatures for ACK.
• New tests.

License

This software is licensed as Apache 2.0.