On August 20, 2019 5:19:33 PM GMT+02:00, Nathan Sidwell <nat...@acm.org> wrote: >On 7/26/19 6:03 AM, Iain Sandoe wrote: >> Hello Sebastian, >> >>> On 26 Jul 2019, at 10:19, Florian Weimer <fwei...@redhat.com> wrote: > >>> C++ coroutines are stackless. I don't think any new low-level >run-time >>> support will be needed. >> >> correct, C++20 coroutines and threading mechanisms are orthogonal >> facilities; one can use (IS C++20) coroutines on top of a threaded >system >> or in a single-threaded environment. >> >> Two places I see them as being a go-to facility in embedded systems >are: >> * co-operative multi-tasking UIs on single-threaded platforms. >> * async I/O completion by continuations, rather than callbacks. > >There are cases where the overhead of threads is too expensive. For >instance hiding (cache-missing) load latencies by doing other work >while >waiting -- a context switch at that point is far too expensive.
But are coroutines so much lower latency (and a context switch does not involve cache misses on its own?). For doing useful work in this context CPU designers invented SMT... Richard. >nathan
