Garbage collection for Rust: The finalizer frontier

Post by guelo » Wed, Oct 15, 2025, 7:29 PM UTC

gizmo686 wrote: post #39

procaryote wrote: post #25

Earlier quoted context omitted.

Hello world in java is pretty fast. Not rust fast but a lot faster than you'd expect. Java starting slowly is mostly from all the cruft in the typical java app, with springboot, dependency injection frameworks, registries etc. You don't have to have those, it's just that most java devs use them and can't conceive of a world of low dependencies Still not great for commandline apps, but java itself is much better than…

Testing on my machine, Hello World in java (openjdk 21) takes about 30ms. In contrast, "time" reports that rust takes 1ms, which is the limit of it's precision. Python does Hello World in just 8ms, despite not having a separate AOT compilation step. The general guidance I've seen for interaction is that things start to feel laggy at 100ms; so 30ms isn't a dealbreaker, but throwing a third of your time budget at the b…

Post by seivan » Wed, Oct 15, 2025, 7:31 PM UTC

jrop wrote: post #15

jvanderbot wrote: post #6

Earlier quoted context omitted.

You've just listed "Compiled language" features. Only the 4th point has any specificity to Rust, and even then, is vague in a way that could be misinterpreted. Rust's predominant feature, the one that brings most of its safety and runtime guarantees, is borrow checking. There are things I love about Rust besides that, but the safety from borrow checking (and everything the borrow checker makes me do) is why I like pr…

Just going to jump in here and say that there's another reason I might want Rust with a Garbage Collector: The language/type-system/LSP is really nice to work with. There have indeed been times that I really miss having enums + traits, but DON'T miss the borrow checker.

Post by [deleted] » Wed, Oct 15, 2025, 7:34 PM UTC

guelo wrote: post #71

gizmo686 wrote: post #39

Earlier quoted context omitted.

Testing on my machine, Hello World in java (openjdk 21) takes about 30ms. In contrast, "time" reports that rust takes 1ms, which is the limit of it's precision. Python does Hello World in just 8ms, despite not having a separate AOT compilation step. The general guidance I've seen for interaction is that things start to feel laggy at 100ms; so 30ms isn't a dealbreaker, but throwing a third of your time budget at the b…

I'm trying and failing to imagine a situation where 30ms startup time would be a problem. Maybe some kind of network service that needs to execute a separate process on every request?

Post by fithisux » Wed, Oct 15, 2025, 7:39 PM UTC

Post by astrange » Wed, Oct 15, 2025, 7:41 PM UTC

ltratt wrote: post #37

nu11ptr wrote: post #29

While it might be useful for exploration/academic pursuit/etc., am I the only one who finds "conservative GC" a non-starter? Even if this was fully production ready, I had a use case for it, etc. I still would never ship an app with a conservative GC. It is difficult enough to remove my own bugs and non-determinism, and I just can't imagine trying to debug a memory leak caused due to a conservative GC not finding all…

If you've used Chrome or Safari to read this post, you've used a program that uses (at least in parts) conservative GC. [I don't know if Firefox uses conservative GC; it wouldn't surprise me if it does.] This partly reflects shortcomings in our current compilers and in current programming language design: even Rust has some decisions (e.g. pointers can be put in `usize`s) that make it hard to do what would seem at fi…