CPU profiling basics in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is CPU profiling in Node.js?

CPU profiling is a way to measure where your Node.js application spends most of its processing time. It helps find slow parts of the code to improve performance.

beginner

Which built-in Node.js tool can you use to start CPU profiling?

You can use the built-in --inspect flag with Node.js and connect Chrome DevTools to start CPU profiling.

beginner

What does a CPU profile output usually show?

It shows a breakdown of functions and how much CPU time each function used, helping you see which parts of your code are slow.

beginner

Why is it important to profile CPU usage in Node.js applications?

Profiling helps find bottlenecks that slow down your app. Fixing these can make your app faster and use less CPU power.

intermediate

How do you start CPU profiling using Chrome DevTools with Node.js?

Run Node.js with node --inspect yourApp.js, open Chrome, go to chrome://inspect, connect to your app, then open the Profiler tab to start recording CPU usage.

What is the main purpose of CPU profiling in Node.js?

A To find which code parts use the most CPU time

B To check memory leaks

C To debug syntax errors

D To monitor network requests

CPU profiling focuses on measuring CPU time usage to find slow code parts.

Which command starts Node.js with debugging enabled for profiling?

A node --trace yourApp.js

B node --profile yourApp.js

C node --debug yourApp.js

D node --inspect yourApp.js

The --inspect flag enables debugging and profiling via Chrome DevTools.

Where do you open Chrome DevTools to connect to a Node.js process for profiling?

A chrome://inspect

B chrome://flags

C chrome://extensions

D chrome://settings

The chrome://inspect page lets you connect to Node.js processes for debugging and profiling.

What does a CPU profile NOT show?

A Functions using most CPU time

B Memory usage details

C Call stacks of functions

D Time spent in each function

CPU profiles focus on CPU time, not memory usage.

Why should you fix bottlenecks found by CPU profiling?

A To add more features

B To increase CPU usage

C To make the app faster and more efficient

D To reduce disk space

Fixing bottlenecks improves app speed and reduces CPU load.

Explain how to start CPU profiling for a Node.js app using Chrome DevTools.

Think about the steps from starting Node.js to recording in DevTools.

Describe why CPU profiling is useful when working with Node.js applications.

Consider what problems profiling helps solve.