On Fri, Aug 16, 2019 at 8:09 PM <dr.ch.mau...@gmail.com> wrote: > The Go-Scheduler is unable to allow to switch to another goroutine in > busy-waiting-loops - > the only possibility to get around that problem is either to put > "switch-steps" into the source > - either "time.Sleep(1)" or "runtime.Gosched()". > I think that THIS SHOULD BE DOCUMENTED IN THE LANGUAGE SPECIFICATION !!!!! > > Usually, you want implementation specific quirks to be part of a description of the implementation, not of the language specification. The reason for this being that it allows a certain amount of leeway in implementations to improve. The typical exceptions to this case is when an implementation detail is so important that the language will not function properly without. A good example are the Scheme specifications (r7rs.org) in which any implementation must implement proper tail-call optimization. But r7rs leaves the execution order of parameters in function calls unspecified. The latter somewhat breaks semantics in the presence of side effects, but it allows implementations to choose the order in which they want to evaluate parameters.
The key here is a trade-off between efficiency and concurrency. Adding checks to tight loops are bound to make that loop slower in some way, or impose a considerable complexity into the language runtime. Most programs caring about concurrency are unlikely to ever hit the problem, provided they synchronize properly, because the synchronization is a possible rendezvous point. If we add forced preemption into the language specification, we prohibit language implementations to make this trade-off. You might then argue this is bad design anyway, to which I respond: "Have you ever seen Javascript, Python or C++?" -- J. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAGrdgiWxuMh68ugdrb0n8rCj8Ai46NBfa8bxktJtjCCbCHeTxA%40mail.gmail.com.
