Thread

1. SamInTheShell · 1790469542 · focus · HN ↗

   The concurrency and threading in Go just feels like magic compared to every other language. I'm a goroutine addict and I refuse to be rehabilitated.

   Just from observations over the years, I don't think there's any other language quite like this, in terms of how things can end up happening in any thread.

   1. osigurdson · 1790472477 · focus · HN ↗

      >> in terms of how things can end up happening in any thread

      Doesn't that describe pretty much any green thread style concurrency implementation.

      1. dlisboa · 1790477447 · focus · HN ↗

         No. Preemptive scheduling plus M:N mapping combination that Go has is not common in other major implementations.

         Other languages and their implementations of green threads usually have cooperative scheduling or M:1 mapping

         1. dwattttt · 1790478303 · focus · HN ↗

            I'm curious; using hardware threads is M logical threads preemptively scheduled on N physical cores. In what way does this not satisfy the original criteria?

            1. dlisboa · 1790478623 · focus · HN ↗

               That's just not what is referred to as green threads.

               1. dwattttt · 1790481873 · focus · HN ↗

                  Yes, in implementation they are not. I'm curious what the difference in subjective experience is.

                  1. falserum · 1790491319 · focus · HN ↗

                     Green threads don’t allocate stack frames and do not require such a massive context switch, which in turn allows for many more threads.

                     1. LtWorf · 1790494597 · focus · HN ↗

                        But if you happen to call a blocking syscall everything breaks.

                        1. jeremyjh · 1790519974 · focus · HN ↗

                           That is not true of preemptive green threading systems. Go/Erlang/Haskell all run native foreign code on its own threads, and manage all internal I/O with async schedulers that never block. They also preempt user code in tight loops.

                           Those are the only mature languages that have all of these features.

                           1. gf000 · 1790539381 · focus · HN ↗

                              Not sure if purposefully but you left out java. It doesn't preempt a CPU hot loop, but arguably you don't really want to disturb the CPU there / the whole "green thread" model doesn't make much sense with that kind of workload. That's why you have ordinary threads as well.

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