Ruby Thread Pool

A thread pool is a group of pre instantiated reusable threads that are available to perform work as needed.

Ruby thread pool.

To start a new thread just associate a block with a call to thread new. Higher level abstractions use global thread pools by default for running asynchronous operations without creating new threads more often than necessary. Spawning one thread for each task is potentially expensive as threads are not free. Thread pool a ruby antihero understanding a fundamental ruby abstraction for concurrency one of the fundamental concepts in key ruby libraries that embrace concurrency is the thread pool.

Ruby thread pool a thread pool is useful when you wish to do some work in a thread but do not know how much work you will be doing in advance. Ruby threads are a lightweight and efficient way to achieve concurrency in your code. These executors are lazy loaded so they do not create overhead when not needed. Thread future accepts an optional argument of type thread pool if you want the block executed in an existing thread pool.

Require rubygems require thread pool pool threadpool new threads 10 pool execute puts i m writing from a thread pool join it s often useful to make sure that the properties of ruby s blocks don t bite you. Concurrent ruby provides several global thread pools. In the following example we are using the celluloid gem to do this for you. By default thread future executes the block in a newly created thread.

Each thread should be wrapped before it runs application code so if your application manually delegates work to other threads such as via thread new or concurrent ruby features that use thread pools you should immediately wrap the block. You could build your own pool but i wouldn t recommend it. You can find examples of thread pool implementations in gems like puma concurrent ruby celluloid pmap parallel and ruby thread. A simple executor style threadpool for ruby with tests yay usage.

Thread pools are particularly useful when there are a large number of short tasks to be performed rather than a small number of longer tasks. Thread pools allow you to control the number of active threads at any given time. Celluloid is now unmaintaned but the general idea of worker pools still applies. A future is somewhat a promise except you pass it a block to execute in another thread.

A new thread will be created to execute the code in the block and the original thread will return from thread new immediately and resume execution with the next. Fortunately there is a better way.