From 80972f1e0e6b6d409cc4d86202608c22e5ee3e5a Mon Sep 17 00:00:00 2001 From: Dario Nieuwenhuis Date: Thu, 30 Mar 2023 17:55:55 +0200 Subject: executor,sync: add support for turbo-wakers. 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. --- embassy-sync/src/waitqueue/mod.rs | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'embassy-sync/src/waitqueue/mod.rs') diff --git a/embassy-sync/src/waitqueue/mod.rs b/embassy-sync/src/waitqueue/mod.rs index 6661a6b61..6b0b0c64e 100644 --- a/embassy-sync/src/waitqueue/mod.rs +++ b/embassy-sync/src/waitqueue/mod.rs @@ -1,7 +1,11 @@ //! Async low-level wait queues -mod waker; -pub use waker::*; +#[cfg_attr(feature = "turbowakers", path = "atomic_waker_turbo.rs")] +mod atomic_waker; +pub use atomic_waker::*; + +mod waker_registration; +pub use waker_registration::*; mod multi_waker; pub use multi_waker::*; -- cgit