# Threading model Hibiki's bookkeeping is isolated per execution context, and the context is the **fiber** (each thread gets that automatically via its root fiber): - The tracking window (which derived/effect is currently computing) and effect ownership live in [fiber storage](https://docs.ruby-lang.org/en/master/Fiber.html#method-c-5B-5D) (`Fiber[]`), which child fibers inherit — so reads made through an `Enumerator`'s internal fiber still register their dependencies. - Batch state is fiber-local but *not* inherited: a batch belongs to the fiber that opened it, and only that fiber's writes are coalesced. Independent signal graphs on different threads, fibers, or Ractors never interfere. A Ractor can run its own reactive world (signals are unshareable objects, so a graph can't cross a Ractor boundary anyway). What Hibiki does **not** do is synchronize the graph itself: a signal graph is confined to the execution context that uses it, and sharing one graph between concurrently running threads is not supported — same single-threaded worldview as Solid and Svelte.

Threading model

Hibiki’s bookkeeping is isolated per execution context, and the context is the fiber (each thread gets that automatically via its root fiber):

• The tracking window (which derived/effect is currently computing) and effect ownership live in fiber storage (Fiber[]), which child fibers inherit — so reads made through an Enumerator’s internal fiber still register their dependencies.
• Batch state is fiber-local but not inherited: a batch belongs to the fiber that opened it, and only that fiber’s writes are coalesced.

Independent signal graphs on different threads, fibers, or Ractors never interfere. A Ractor can run its own reactive world (signals are unshareable objects, so a graph can’t cross a Ractor boundary anyway).

What Hibiki does not do is synchronize the graph itself: a signal graph is confined to the execution context that uses it, and sharing one graph between concurrently running threads is not supported — same single-threaded worldview as Solid and Svelte.