Re:Modern garbage collection: Part 2
by zozbot234 on Sunday December 15, 2019 @08:22AM
(#21796094)
> instruction pollution from all the refcount updates and their synchronization
If the language supports ownership tracking and non-synchronized Rc<> as in Rust, refcount updates ought to be rare and/or quick. I agree that this is very much an issue in languages with obligate "managed" memory such as Swift, and that tracing GC may sometimes be preferable to that.
> too much time spent freeing memory
If you're using Rc, you probably care about memory reclaim being deterministic, which tracing GC doesn't give you. You can also use arenas to free a bunch of objects all at once; this also addresses memory fragmentation and slow allocation to some extent.
If the language supports ownership tracking and non-synchronized Rc<> as in Rust, refcount updates ought to be rare and/or quick. I agree that this is very much an issue in languages with obligate "managed" memory such as Swift, and that tracing GC may sometimes be preferable to that.
> too much time spent freeing memory
If you're using Rc, you probably care about memory reclaim being deterministic, which tracing GC doesn't give you. You can also use arenas to free a bunch of objects all at once; this also addresses memory fragmentation and slow allocation to some extent.