ASashvardanian·Apr 18, 2025
Great question! This has been top of mind for me for the last 2–3 years.
Short answer: sadly, no. I love the "usability" promise of coroutines—and even have 2–3 FOSS projects that could be rewritten entirely around C++ or Rust coroutines for better debuggability and extensibility—but my experiments show that the runtime cost of most coroutine‑like abstractions is simply too high. Frankly, I’m not even sure if a better design is possible on modern hardware.
This leads me to conclude that, despite my passion for SIMD and superscalar execution, the highest‑impact new assembly instructions that x86 and Arm could standardize would center on async execution and lightweight context switching... yet I haven’t seen any movement in that direction.
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I also wrote toy examples for various range/async/stream models in C++, Rust, and Python, with measu
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red latencies in inline comments:
- Python: <https://github.com/ashvardanian/less_slow.py/blob/2c80c9dda6ef9aec18264871cfb51a13…>
- C++: <https://github.com/ashvardanian/less_slow.cpp/blob/8f32d65cc8976ad20c8cdf645caa5b3…>
- Rust: <https://github.com/ashvardanian/less_slow.rs/blob/5add609533854bb6a5ddbf358cc15f06…>
Aside from coroutines (toy hand-rolled implementations and commonly used libraries), I've also played around C++ executors, senders & receivers, but didn't have much success with them either. May be a skill issue.