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Comment by archargelod

8 hours ago

> GC languages are slower

This is not necessarily true. It depends on a language, e.g. Go is slow, Nim[0] is extremely fast with conventional GC and slightly faster with ARC/ORC[1].

GC programs can be faster than manually managed ones in some cases. It's just manual memory management gives you more control of where and when free is called. And a good type system is a privelege that gives Nim more control with destructors.

Another scarecrow of safe languages is GC pauses, which is also not a thing in Nim, see table in [2].

[0] - https://nim-lang.org/

[1] - https://nim-lang.org/blog/2020/10/15/introduction-to-arc-orc...

[2] - https://nim-lang.github.io/Nim/mm.html

9 comments

archargelod

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seanmcdirmid  8 hours ago

You can always use things like arenas in C and get similar speed ups without GC overhead. If you know your memory lifetimes in advanced, avoiding granular malloc/free calls is pretty straightforward. A GC language doesn’t usually offer such options.

josephg  8 hours ago

Good to know! Would there be any way languages like Go or C# could adopt Nim's new garbage collector? If it's better, what stops other languages from using it?

> GC programs can be faster than manually managed ones in some cases.

I've seen poorly written programs in C/C++/Rust which are slow because they allocate millions of tiny objects. Its true that generational GCs can be faster in this case. But you usually get much better performance again by using arenas and such. The reality is that I know more about the lifecycle of my data than my compiler. If you know what you're doing, you can take advantage of this information to write better programs.

If you don't want to think about memory management, then I agree - you're usually better off using a language with a GC. Personally I do a lot of my prototyping in typescript because I can iterate faster when I don't have to think about lifetimes.

Maybe some day Fil-C will run general purpose C code at native speeds, without a high memory overhead. But we're not there yet. I'm not holding my breath.

  • galangalalgol  1 minute ago

    Even if you don't think about memory management, and do the naive thing in rust or rc in some other systems language, gc only comes out ahead in that many tiny objects case. Which is very domain specific. I don't ever run into that situation, or if I do, they are homogeneous in type so I handle them in bulk, not individually.