VM Matters: A Comparison of WASM VMs and EVMs in the Performance of Blockchain Smart Contracts

TL;DR

This study compares the performance of WebAssembly (WASM) VMs and Ethereum Virtual Machines (EVMs) in executing blockchain smart contracts, revealing unexpected performance issues with current WASM implementations.

Contribution

First measurement study comparing WASM VMs and EVMs for blockchain smart contracts, highlighting performance challenges of WASM in this context.

Findings

WASM VM does not outperform EVM as expected

WASM introduces significant overhead in blockchain execution

Results suggest need for optimization in WASM deployment

Abstract

WebAssemly is an emerging runtime for Web applications and has been supported in almost all browsers. Recently, WebAssembly is further regarded to be a the next-generation environment for blockchain applications, and has been adopted by Ethereum, namely eWASM, to replace the state-of-the-art EVM. However, whether and how well current eWASM outperforms EVM on blockchain clients is still unknown. This paper conducts the first measurement study, to measure the performance on WASM VM and EVM for executing smart contracts on blockchain. To our surprise, the current WASM VM does not perform in expected performance. The overhead introduced by WASM is really non-trivial. Our results highlight the challenges when deploying WASM in practice, and provide insightful implications for improvement space.