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No. Implicitly yielding and getting scheduled back is exactly what synchronous sequence is. And it cannot ever be faster than asynchronous, because asynchronous
by zzzcpan 9y ago
No. Implicitly yielding and getting scheduled back is exactly what synchronous sequence is. And it cannot ever be faster than asynchronous, because asynchronous doesn't yield. Any "rediscoveries" are just mistakes due to lack of fundamental understanding of these things.
- k__ 9y agoSo where are the benefits coming from in these "rediscoveries"?
- zzzcpan 9y agoSometimes async is not real async, but an emulation, this is where "rediscoveries" come in I suppose.
- rictic 9y agoAll of these examples are running on preemptive multithreaded operating systems, so implicitly yielding and getting scheduled is in the cards even if your process is managing its own concurrency with cooperative multithreading.
- masklinn 9y ago> No. Implicitly yielding and getting scheduled back is exactly what synchronous sequence is. Your asynchronous system can be descheduled by the OS on top of the stuff it does on its own if it runs on a preemptive multitasking OS or hypervisor, which more or less all of them do. > And it cannot ever be faster than asynchronous, because asynchronous doesn't yield. The asynchronous system yields doubly, it yields to its own userland scheduler/event loop and it's de-scheduled by the preemptive multitasking OS it runs on top of.
- zzzcpan 9y agoAny process or thread can be descheduled by the OS on top of the stuff it does on its own. Yielding is a thing from the multithreaded world with synchronous APIs. Asynchronous systems don't yield, they are programmed asynchronously. They have no yielding overhead and can never be slower than yielding threads. If you are arguing for 1:1 kernel threading against M:N threading (coroutines, goroutines, green threads) that's fine, but multithreading implementations have absolutely nothing to do with asynchronous systems.
- zbentley 9y agoIt seems like the two of you disagree fundamentally on what "asynchronous" means in this context. https://en.wikipedia.org/wiki/Asynchrony_(computer_programming) https://en.wikipedia.org/wiki/Asynchrony_(computer_programmi...
- zzzcpan 9y agoI don't think we disagree on that, since he explicitly mentions event loops and essentially claims they are generally slower. Which is nonsense.