Thread

Go Concurrency Distilled

402 points · 187 comments · chmaynard

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. za3faran · 1790483757 · focus · HN ↗
  Java is doing it better (virtual threads + structured concurrency + immutable records and immutable value types).
  Not to mention golang is not memory safe: <a href="https://www.ralfj.de/blog/2025/07/24/memory-safety.html" rel="nofollow">https://www.ralfj.de/blog/2025/07/24/memory-safety.html
  1. SamInTheShell · 1790485224 · focus · HN ↗
    I don't think you understand the threading concurrency topic. Also memory safety is so far off base here, where's that coming from? Java does some stuff okay, but do you really want to defend the horrid JVM problems? Also why can't I have my memory back when it's not in use in tightly packed systems?
    It's not great for everything and neither is Go. You can find a bit more context on that in some of the other threads.
    gf000 · 1790512246 · focus · HN ↗
    > defend the horrid JVM problems
    Such as? It's one of the most widely used platform for backend services, basically almost all top 500 company has some business critical infrastructure running Java. It surely can't have "too horrid" problems..
    SamInTheShell · 1790540089 · focus · HN ↗
    I gave an example. Go allocate 8 gigs. Then get it garbage collected. Why is JVM still allocating 8 gigs?
    za3faran · 1790542734 · focus · HN ↗
    We have Java services running on 512MB k8s nodes.
    Furthermore, collection time (for moving collectors) is a function of the liveset, not the # of dead objects.
    SamInTheShell · 1790618576 · focus · HN ↗
    Still doesn't answer the question. In Java, allocate 8 gigs. Free 7 gigs. Why still 8 gigs? I didn't ask anything about if I could run a 1 gig process here.
    za3faran · 1790652000 · focus · HN ↗
    It depends on the GC settings. With the other JEPS I listed, things should become more aggressive. But today you can have:
    > java -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10 test.java used=7640 MB, committed=7668 MB, max=8192 MB used=4 MB, committed=20 MB, max=8192 MB used=3 MB, committed=8 MB, max=8192 MB used=3 MB, committed=8 MB, max=8192 MB
    The RSS drops from ~8GB to 8 MB.

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