Suspendable computations like regex statemachines are actually a good example use case. However I'd still categorize this as extremely marginal. I have seen lit

Suspendable computations like regex statemachines are actually a good example use case. However I'd still categorize this as extremely marginal. I have seen literally zero Rust crates that handle suspendable computations (ofc outside of the scheduler runtime). Also note that by their nature regex statemachines do not actually necessitate the use of async, it's effectively syntax sugar on top. My point with GPU/FPGA is that if you're at the point where this level of optimization matters then you're actually dealing with situations where it's worth to invest in the big boy tools. Examples are HPC in fintech (low latency trading) and scientific computations, game development, video codecs etc. You know, "actual" computations. Webservices are not in this category. Generally speaking with web services your goal is to "hide in the shadow of IO". If you max out your network and/or database and/or filesystem capacity, further CPU optimizations will have literally no effect. I have yet to encounter a web service where this wasn't the case. What I do see sometimes with webservices is simply unnecessary compute, bad internal structuring, dynamic dispatch, parallelism overcommit, lack of batching, fragmented apis, fragmented data accesses etc etc all of which appear as CPU capacity saturation and also sometimes as kernelspace overhead in profiles. Async does not help solving any of these issues. And once you do solve them, you reached IO boundness and it doesn't matter anymore. Again this is just my experience, and I'm happy to learn about what kind of web service can utilize coroutines with measurable performance benefits over a managed threadpool.