ephemerons

Our novel design minimizes the number of global synchronizations necessary for collecting a deeply nested hierarchy of ephemerons.

Would moving the dependents list to an instance variable holding a weak array avoid the need for ephemerons here?

Well, WeakMap implementations (like WeakKeyDictionary) that don't delay GC significantly do indeed use ephemerons.

Another example would be support for ephemerons, which are more powerful than weak references.

I'm not sure the garbage collectors have all the necessary support for weird stuff like weak boxes and ephemerons.

But, if you use ephemerons with not so many objects, let's say a couple of houndreds max, you should not have any issue.

For example ephemerons, that need some magic to cooperate with the garbage collector.

So it may be considered missing part of the definition of ephemerons.

Sometimes it can get worse, like when you add concepts like ephemerons.

It depends on how many objects you installed the ephemerons.

We tested with hundreds of thousands of ephemerons and we saw performance problems.

Also worth pointing out there's design constraints on the OCaml 5 GC imposed by some of OCaml's language features (looking at you ephemerons) and C API invariants.

In practice, you probably don't want to do those lookups until you've traversed the "easy" part of the heap that doesn't require traversing ephemerons to get to.

Ephemerons are often used when you can't attach data directly to either the key object or the value object.

Lists, Hashtables, Maps, Strings, Refcounted pointers, Weak pointers, Ephemerons, iterators for mentioned?