Insights into WebAssembly: Compilation Performance and Shared Code Caching in Node.js Tobias Nießen Michael Dawson Faculty of Computer Science IBM Runtime Technologies University of New Brunswick IBM Canada
[email protected] [email protected] Panos Patros Kenneth B. Kent Software Engineering Faculty of Computer Science University of Waikato University of New Brunswick
[email protected] [email protected] ABSTRACT high-level languages, the WebAssembly instruction set is closely re- Alongside JavaScript, V8 and Node.js have become essential com- lated to actual instruction sets of modern processors, since the initial ponents of contemporary web and cloud applications. With the WebAssembly specification does not contain high-level concepts addition of WebAssembly to the web, developers finally have a fast such as objects or garbage collection [8]. Because of the similarity of platform for performance-critical code. However, this addition also the WebAssembly instruction set to physical processor instruction introduces new challenges to client and server applications. New sets, many existing “low-level” languages can already be compiled application architectures, such as serverless computing, require to WebAssembly, including C, C++, and Rust. instantaneous performance without long startup times. In this pa- WebAssembly also features an interesting combination of secu- per, we investigate the performance of WebAssembly compilation rity properties. By design, WebAssembly can only interact with its in V8 and Node.js, and present the design and implementation of host environment through an application-specific interface. There a multi-process shared code cache for Node.js applications. We is no built-in concept of system calls, but they can be implemented demonstrate how such a cache can significantly increase applica- through explicitly imported functions.