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Comment by pron

1 day ago

Java lost almost all those knobs a while ago (I mean they're there, but you're better off relying on the defaults). The modern GCs have one or at most two knobs remaining, and even that will become unnecessary next year. As to predictablity, you get maximal pause time of well under 1ms for heaps up to 16TB.

15 comments

pron

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JackSlateur  19 hours ago

As far as I know, java has 7 GC implementations, none of which are perfect, all of which have drawbacks

Lately, they seems to work with CRIU, various heuristics, multi-stage in-process bytecode compilation ..

Java is a mess, they are working hard to avoid fixing their issue (that nobody else have, so fixes are available)

  • coldtea  18 hours ago

    >As far as I know, java has 7 GC implementations, none of which are perfect, all of which have drawbacks

    Compared to Python's, all of them are beyond perfect. And 99.9% of the time you don't even need to use anything but the default.

    • refulgentis  16 hours ago

      > Compared to Python's, all of them are beyond perfect.

      I somehow understand the situation less after reading this.

      Is Python's GC bad, or are there cyclic reference issues? Is it possible to detect cyclic references perfectly? What does beyond perfect mean? If we have 7 and 0.1% of the time you need one of the 6 that is non-default, how do we choose? Is the understated version of "Compared to Python's, all of them are beyond perfect" "I think Java's are great"? If not, what about Python's impl makes it so lackluster to any of 7 of Java's?

      6 replies →

  • pron  3 hours ago

    > Lately, they seems to work with CRIU, various heuristics, multi-stage in-process bytecode compilation ..

    Not sure what you mean by this, as this has nothing to do with GC, and Java has had a multi-tier optimising compiler for 15 years now.

    > that nobody else have, so fixes are available

    Go has much worse problems with GC than Java does these days, and nobody else is able to achieve similar performance in large programs with heavy workloads. So everyone else lives with less sophisticated compilers and memory management simply by accepting worse performance.