Concurrency in Ruby: Threads, Fibers, and Ractors Demistified

Concurrency in Ruby: Threads, Fibers, and Ractors Demystified

Magesh S presents an informative talk on concurrency in Ruby, exploring its evolution and the newly introduced concurrency features like threads, fibers, and Ractors. The discussion emphasizes the importance of utilizing CPU resources efficiently and boosting Ruby application performance. Here are the key points covered in the talk:

Understanding Concurrency vs. Parallelism
- Concurrency is about managing multiple tasks at once without executing them simultaneously.
- Parallelism executes multiple tasks simultaneously.
Historical Context
- Ruby traditionally relied on threads for concurrency, which many developers found challenging.
- The release of Ruby 3.0 introduced fibers and Ractors as enhancements to address concurrency in a more user-friendly and efficient manner.
Threads
- Allow concurrent execution in Ruby but not true parallelism due to the Global Interpreter Lock (GIL), which limits execution to one thread at a time in MRI Ruby.
- Example: Magesh demonstrates how threads can be used to speed up I/O-bound operations like API calls, reducing execution time significantly.
- Challenges with threads include race conditions and deadlocks, requiring careful synchronization through locks to avoid inconsistencies.
Fibers
- Light-weight, user-managed alternatives to threads that allow for more efficient concurrency without the overhead of OS-level context switching.
- Magesh shows how fibers can be utilized for I/O-bound tasks while providing a structured way to yield control and resume execution, enhancing performance.
- Cautions regarding fibers include the need for proper management of control yielding to avoid starvation between fibers.
Ractors
- Introduced for true parallel processing in Ruby, allowing multiple light-weight processes to operate simultaneously without shared memory, thus avoiding race conditions altogether.
- Example use case: Magesh illustrates processing large CSV files across multiple Ractors for parallelized performance improvements.
- Limitations include immutability requirements for shared data and the current experimental nature of Ractors with some library compatibility issues.

In conclusion, Magesh emphasizes that:
- Threads and fibers are best for I/O-bound tasks, while Ractors are suited for CPU-intensive operations.

- Understanding the strengths and trade-offs of threads, fibers, and Ractors helps developers choose the right approach for their Ruby applications. The talk encourages developers to experiment with these concurrency features to enhance application efficiency.

Concurrency in Ruby: Threads, Fibers, and Ractors Demistified
Magesh S • Sarajevo, Bosnia and Herzegovina • Talk

Date: September 12, 2024
Published: January 13, 2025
Announced: unknown

Speed up your Ruby applications with the power of concurrency! Join us as we demystify threads, fibers, and Ractors, understanding their unique strengths, use cases, and impact on Ruby performance. Learn to tackle I/O bottlenecks and enable parallel execution, boosting your code’s speed.

For a very long time, Ruby had limited options for concurrency, mainly relying on threads, which developers often dreaded. However, with the exciting updates introduced in Ruby 3.0, the fiber scheduler and Ractors provided a remarkable 3x performance boost. Despite these advancements, few have used these features in production. But now, we can confidently say that they are ready for use.

EuRuKo 2024