This is a `core` patch to make wakers 1 word (the task pointer) instead of 2 (task pointer + vtable). It allows having the "waker optimization" we had a while back on `WakerRegistration/AtomicWaker`, but EVERYWHERE, without patching all crates.
Advantages:
- Less memory usage.
- Faster.
- `AtomicWaker` can actually use atomics to load/store the waker, No critical section needed.
- No `dyn` call, which means `cargo-call-stack` can now see through wakes.
Disadvantages:
- You have to patch `core`...
- Breaks all executors and other things that create wakers, unless they opt in to using the new `from_ptr` API.
How to use:
- Run this shell script to patch `core`. https://gist.github.com/Dirbaio/c67da7cf318515181539122c9d32b395
- Enable `build-std`
- Enable `build-std-features = core/turbowakers`
- Enable feature `turbowakers` in `embassy-executor`, `embassy-sync`.
- Make sure you have no other crate creating wakers other than `embassy-executor`. These will panic at runtime.
Note that the patched `core` is equivalent to the unpached one when the `turbowakers` feature is not enabled, so it should be fine to leave it there.
1054: riscv fixes r=lulf a=swolix
With these changes I can run embassy on our RISC-V processor, please consider merging this, feedback is very welcome.
I don't fully understand the code in the executor, but I have implemented a critical section by globally disabling interrupts, which means the wfi inside the critical section will hang the whole thing.
Co-authored-by: Sijmen Woutersen <sijmen.woutersen@gmail.com>
Add "rtos-trace-interrupt" feature flag on embassy-macros and enable it
for embassy-executor, to ensure that the interrupt::take! macro can be
used without depending on embassy-executor.
This fixes the WASM support which was failing due to missing
critical-section implementation. This also upgrades the bindgen
dependency and ensures that tooling works.
