Wasmtime, being an optimizing JIT, usually is ~10 times faster than Wasmi during execution.

However, execution is just one metric that might be of importance.

For example, Wasmi's lazy startup time is much better (~100-1000x) since it does not have to produce machine code. This can result in cases where Wasmi is done executing while Wasmtime is still generating machine code.

Old post with some measurements: https://wasmi-labs.github.io/blog/posts/wasmi-v0.32/

Always benchmark and choose the best tool for your usage pattern.

That's a good point I didn't think about.

I guess it's like v8 compared to quickjs.

Anyway all this talk about wasm makes me want to write a scriptable Rust app!