go-wasm-bake VS wizer

> So how does this work? Before the code is deployed, as part of a build step, we run the JS code using the JS engine to the end of initialization.

I also did basically this exact same thing for Go [0] when I realized their initialization in WASM was very heavy[1]. Basically I ran up until the real Go main started which includes a ton of runtime package/data initialization, and took a snapshot of the data and baked it back into the WASM and removed all the pre-main code. Granted this was years ago so I don't know if it still works on generated code today, but the idea is the same.

I think languages compiling to WASM, if they can, should run their initialization code and snapshot the data. A lot of people don't realize the number of init instructions to bootstrap a runtime these days. Go alone has thousands of instructions just to initialize the unicode tables.

0 - https://github.com/cretz/go-wasm-bake

> once by the wasm runtime to compile the rust-python wasm

I'm not sure what you mean by that. The runtime doesn't compile WASM, it simply executes it.

There are tools for dealing with interpreter runtime overhead this by pre-initalizing the environment like Wizer[0]. ComponentizeJS[1] uses it to pre-initialize the Spidermoney engine it packages to gain fast startup times (and you can then prune the initialization only code with wasm-opt). As techniques like ComponentizeJS are also being applied for a specific set of interpreted files, you can even prune parts of the interpreter that would never be used for that specific program. If you want to go even further you could record specific execution profiles and optimize further by those.

[0]: https://github.com/bytecodealliance/wizer

[1]: https://github.com/bytecodealliance/ComponentizeJS

Edge functions are typically run intermittently, with their runtime stopped to free up resources between runs. Therefore a big factor is startup and shutdown speed. Containers are pretty bad there. Deno is better, and WASM is unbeatable, especially with things like Wizer[0].

[0]https://github.com/bytecodealliance/wizer

I imagine startup cost could be amortized by something like wizer: https://github.com/bytecodealliance/wizer

There are security benefits to running each request in its own instance, as it helps prevent accidental leaking of state between requests. To avoid doing lots of expensive initializations, we have a tool called wizer which lets users run their program's initialization once, create a snapshot, and then use that snapshot to do fast startups that don't rerun the whole initialization each time.

See https://github.com/bytecodealliance/wizer for an implementation of this approach.

It should probably be named "Making JavaScript to startup fast on WebAssembly", since the runtime speed is not really improved by the approach they exposed.

Besides that I think Wizer [1] is both an elegant and a simple solution to speed up startup speed with Wasm.

[1] - https://github.com/bytecodealliance/wizer#using-wizer-as-a-l...

A similar project, for WebAssembly so with limited scope is this: https://github.com/bytecodealliance/wizer. And somehow similar but limited on LLVM IR a colleague worked on this for Cheerp (the compiler used here as backend): https://github.com/leaningtech/cheerp-meta/wiki/Cheerp-PreExecuter.