OptSmart: A Space Efficient Optimistic Concurrent Execution of Smart Contracts

TL;DR

This paper introduces OptSmart, a concurrency framework for smart contract execution that leverages optimistic software transactional memory to improve efficiency and throughput in blockchain systems.

Contribution

It presents a novel concurrent miner and validator that execute smart contract transactions in parallel, ensuring correctness and significantly outperforming existing methods.

Findings

Achieves higher throughput than state-of-the-art methods.

Ensures correct concurrent execution of smart contracts.

Demonstrates significant performance improvements.

Abstract

Popular blockchains such as Ethereum and several others execute complex transactions in blocks through user-defined scripts known as smart contracts. Serial execution of smart contract transactions/atomic-units (AUs) fails to harness the multiprocessing power offered by the prevalence of multi-core processors. By adding concurrency to the execution of AUs, we can achieve better efficiency and higher throughput. In this paper, we develop a concurrent miner that proposes a block by executing the AUs concurrently using optimistic Software Transactional Memory systems (STMs). It captures the independent AUs in a concurrent bin and dependent AUs in the block graph (BG) efficiently. Later, we propose a concurrent validator that re-executes the same AUs concurrently and deterministically using a concurrent bin followed by a BG given by the miner to verify the proposed block. We rigorously prove the correctness of concurrent execution of AUs and achieve significant performance gain over the state-of-the-art.