Programming Ruby 3.3

Understanding Ractors

Ruby 3.0 introduced ractors, a Ruby implementation of the Actor pattern for multithreaded behavior. (Experimental support for the feature was originally developed under the name “Guilds.”)

How Ractors Work

Ractors allow true parallelism within a single Ruby interpreter: each ractor maintains its own GIL, allowing for potentially better performance. In order for this to work, ractors have only limited ability to access variables outside their scope and can communicate with each other in only specific, pre-defined ways. (Also, if for some reason you’re running multiple threads inside a single ractor—probably you shouldn’t do this—those threads are subject to the equivalent of a global lock on the ractor and won’t run in parallel.) ...