Ruby Fibers

What are Ruby Fibers?

Ruby fibers are a concurrency primitive that allows you to pause and resume code execution at specific points. Unlike threads, fibers do not run in parallel but rather provide a means for cooperative multitasking. This means that a fiber yields control explicitly to allow other fibers to run.

Fibers are particularly useful in scenarios where you need to manage multiple tasks without the overhead of thread-based concurrency. They can be thought of as lightweight threads with manual control over execution flow.

Creating and Using a Fiber

To create a fiber in Ruby, you use the Fiber.new method, passing a block of code to be executed. You can start a fiber by calling fiber.resume. When a fiber calls Fiber.yield, it pauses its execution, allowing the main thread or other fibers to run.

How Fiber Yielding Works

The Fiber.yield method is crucial for fiber control. When Fiber.yield is called, the fiber pauses and control returns to the calling method or context. Resuming the fiber will continue execution from the point where it yielded.

This cooperative yielding is what differentiates fibers from threads, as threads can be preempted at any point by the scheduler, whereas fibers voluntarily yield control.

Advantages of Using Fibers

• Efficiency: Fibers are more lightweight compared to threads as they do not require context switching.
• Control: You have explicit control over when a fiber yields, which can lead to simpler logic in some cases.
• Resource Management: Less overhead in terms of memory and CPU usage when managing many concurrent tasks.

Limitations of Fibers

• No Parallel Execution: Fibers run in the same thread context and cannot utilize multiple CPU cores.
• Manual Yielding: Requires explicit control of execution flow, which can be complex for large applications.
• Limited Use Cases: Best suited for IO-bound operations rather than CPU-bound tasks.

Fibers vs. Threads

While both fibers and threads are used to achieve concurrency, they serve different purposes. Threads are more suitable for parallel execution and can take advantage of multi-core processors. In contrast, fibers are ideal for cooperative concurrency where tasks are interleaved in a single thread.

Choosing between fibers and threads depends on the specific needs of your application, such as whether you need parallel execution or if you prefer the simplicity and lightweight nature of fibers.