Cooperative multitasking is a style of Concurrency where the responsibility for yielding control rests entirely with individual tasks, rather than being managed by the operating system’s scheduler.
In Ruby Concurrency Mechanisms, Fibers implement this pattern through Coroutines. Each fiber explicitly yields control to allow other fibers to execute, or can be configured to automatically yield when operations become blocked.
Contrast with Preemptive Multitasking
Unlike preemptive multitasking (used by operating system threads), where the scheduler forcibly interrupts tasks, cooperative multitasking requires tasks to voluntarily relinquish control. This gives developers explicit control over context switching but requires careful design to avoid blocking other tasks.
Benefits
Fibers enable efficient resource sharing without the full complexity of low-level threading. They’re lightweight and ideal for O-bound workloads where explicit control flow matters, as demonstrated in Async Ruby frameworks that handle thousands of concurrent connections.
Non-blocking fibers and the Fiber scheduling API were significant enhancements added in Ruby 3.0.