cargo-call-stack VS embassy

Yes, it's what I wrote about in the last paragraph. If you can compute maximum stack size of a function, then you can avoid dynamic allocation with fibers as well. You are right that such implementations do not exist in right now, but I think it's technically possible as demonstrated by tools such as https://github.com/japaric/cargo-call-stack The main stumbling block here is FFI, historically shared libraries do not have any annotations about stack usage, so functions with bounded stack usage would not be able to use even libc.

For rust code, I have found https://github.com/japaric/cargo-call-stack to be the best available option, as it does take advantage of how Rust types are implemented in LLVM-IR to handle function pointers / dynamic dispatch a little better. An even better solution would try to use MIR type information as well to further narrow down targets of dynamic calls in a Rust-specific way, but no such tool exists that I know of.

cargo-call-stack Static stack analysis!

Generators can just dump stuff on the stack. They have additional their own stack for storing their state. If you can prove an upper amount of creation of generators in the call graph, that would however work. There is for example this nice tool for Rust doing the overapproximation.

Not easy at all.

I know that in the small-embedded world, people do work on such things.

Eg https://github.com/japaric/cargo-call-stack

thanks. looked that up. for the curious: https://embassy.dev/

Running the Embassy RP2040 USB CDC ACM serial example takes about 5 seconds on a Pico.

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

Async solves different problems, you can, for instance, have just a single-threaded CPU and still have a nice API if you have async-await. It might not be so cool at a higher level as Go's approach of channels and threads, but it's cool in embedded, read this:

https://github.com/embassy-rs/embassy?tab=readme-ov-file#rus...

"Rust's async/await allows for unprecedently easy and efficient multitasking in embedded systems. Tasks get transformed at compile time into state machines that get run cooperatively. It requires no dynamic memory allocation, and runs on a single stack, so no per-task stack size tuning is required. It obsoletes the need for a traditional RTOS with kernel context switching, and is faster and smaller than one!"

I'm just toying with Raspberry Pi Pico and it's pretty nice.

Go and Rust have different use cases, the async-await is nice at a low level.

I have not yet dipped by toes in the Rust waters, but reading about the embassy project is actually what piqued my curiosity about using C++ coroutines in embedded. Are you familiar with the project or have you found it lacking?

I think I get the basics (shoutout to the Rust Embedded Working Group!), and I've started looking for the stack I'd be using. I think Embassy is really amazing, as well as the work of the ESP team -- hats off.

> }

And this is how to do it using embassy, which is an async framework for embedded in rust:

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

> not good for embedded

embassy begs to differ

https://embassy.dev/

async/await is really just a syntax for building state machines in a way that resembles regular code. It's compiled down to the same code that you would write by hand anyway (early on it had some bloat in state size but I think it's all fixed now).

And embedded has a lot of state machines!

You can run multiple executors at different interrupt priority levels (with multiple tasks per executor), which allows tasks on the higher priority executor to interrupt other tasks. Here's an example https://github.com/embassy-rs/embassy/blob/main/examples/nrf...