Job system
An engine scheduler that breaks a frame into small jobs run across a thread pool with dependencies, so every CPU core stays busy without hand-managed threading.
Rather than spin up one thread per system, it schedules short tasks — "update these 500 particles", "cull this node" — into a pool with one worker per core. A job can declare that it depends on another, so the scheduler builds a dependency graph and runs everything independent in parallel. Idle workers steal jobs from busy queues (work stealing).
Naughty Dog's fiber-based system (GDC 2015) let a job pause and resume cheaply; Unity's C# Job System brought the pattern to a wider audience. The payoff assumes data is laid out in arrays and data-oriented, otherwise the jobs fight over the same cache lines.