Optimizar rendimiento en Node.js con Worker Threads y Child Processes

To improve performance in Node.js applications that perform CPU-intensive tasks, there are specific mechanisms that help prevent the Event Loop from crashing. Exploring techniques such as Worker Threads and Child Processes allow you to handle these heavy tasks efficiently, while maintaining optimal performance on your Express server.

Why does the Node.js Event Loop crash with certain tasks?

Node.js runs JavaScript in asingle thread, known as Event Loop. When performing intensive computations, such as the Fibonacci term number 40, this execution becomes saturated and prevents other requests from being handled in a timely manner. This generates bottlenecks and drastic decreases in capacity and performance. For example:

• A Fibonacci intensive task can significantly reduce the usual capacity (from thousands of requests to a few tens).
• This blocking causes web applications to respond slowly.

How do Worker Threads work to optimize performance?

Worker Threads allow you to shunt CPU-intensive tasks to new, specifically created threads, avoiding interfering with the main thread. To implement it:

1. Import Worker from worker_threads.
2. Create a new Worker pointing to an own JavaScript file(worker.js).

In this file parentPort and workerData are used to communicate results from the Worker to the main process. This keeps the main thread available for other requests.

Results of using Workers shown with Autocannon:

• Successful requests increased considerably.
• The Event Loop became free, showing lower latency and better performance.

What do Child Processes offer to handle these tasks?

Another option is to use Child Processes, which spawn new independent Node.js processes. They are mainly used with the fork method of the child_process module. Things to consider:

• Each Child is a completely independent process.
• Communication between processes via message events using process.send() and listener events.
• Indicated CPU is higher, distributed among multiple individual processes.

Results of using Child Processes:

• Showed good speed and prevention of Event Loop deadlock.
• Similar capacity, although slightly lower compared to Workers in specific tests.

Which to choose: Workers Threads or Child Processes?

Consider these recommendations based on proven performance tests:

• Worker Threads are advisable for performing purely JavaScript heavy tasks, optimizing the use of shared resources.
• Child Processes offer additional advantages, such as executing operating system commands and using advanced functionality (Spawn), ideal when the application needs to interact directly with the host.

Both techniques are effective tools and depending on the situation can offer specific advantages that directly impact the overall performance of Node.js applications.

What has been your experience using Workers or Child Processes in Node? Share your comments!