Wasmtime WebAssembly runtime set for 1.0 release

Wasmtime, a standalone runtime for WebAssembly, is nearing its official 1.0 release.

A project from the Bytecode Alliance, Wasmtime is due to reach 1.0 status on September 20, the group said in a September 6 blog post. Wasmtime runs WebAssembly code outside of the web. It is intended to be a configurable, embeddable runtime to run on any scale of application. WebAssembly, or Wasm for short, is a binary instruction format for a stack-based virtual machine, serving as a compilation target for programming languages and enabling web deployment of client and server applications.

For the upcoming release, the Wasmtime developers have focused on making the compiler generate faster code, making Wasmtime instantiate a compiled module faster, and making the runtime as efficient as possible once a module is running. Work also has been done to ensure that the runtime is secure and that the compiler produces correct code. Installation instructions for Wasmtime can be found at wasmtime.dev.

Wasmtime was built on the Cranelift code generator, which generates machine code either at runtime or ahead of time. Wasmtime has been optimized for efficient instantiation, low-overhead calls between the embedder and WebAssembly, and scalability of concurrent instances.

When Wasmtime executes a WebAssembly program, the CPU executes both native instructions compiled from the WebAssembly bytecode and parts of the Wasmtime runtime that maintain data structures to help implement WebAssembly semantics. Work has been done to improve the startup phase, which covers time to compile code and time to instantiate a Wasm module, as well as the steady-state phase, which covers the speed of generated code and speed of runtime primitives. Cranelift also has been optimized, with plans calling for further optimizations.