📌 What is Network I/O?

🧵 Thread Pool & Async Methods

• Libuv's thread pool helps execute some async methods, but not all.
• Example: crypto.pbkdf2() uses the thread pool, whereas https.request() does not.

🔹 Result of Experiments

• Although both crypto.pbkdf2() and https.request() are asynchronous, https.request() does not use the thread pool.
• The behavior of https.request() is not affected by the number of CPU cores.

🔹 Network I/O Behavior

• https.request() is a network I/O operation, not CPU-bound.
• Libuv passes the work to the operating system kernel and periodically checks if the request has completed.

⚙️ Kernel in Operating System

• The kernel is the central component of an operating system managing hardware and software operations.
• It manages CPU, memory, devices, and system resources efficiently.
• Acts as a bridge between software applications and hardware.
• Handles running programs, accessing files, and connecting devices like printers and keyboards.

🔹 Network I/O Execution

• Libuv passes network tasks to the OS kernel and checks completion without blocking the main thread.

📌 Summary – Libuv & Async Methods

• Async methods in Node.js are handled by Libuv in 2 way:
• 1. Native async mechanisms (preferred if available)
• 2. Thread Pool (used for file I/O or CPU-intensive tasks if no native async support)
• Libuv leverages OS-specific mechanisms: epoll (Linux), kqueue (MacOS), IOCP (Windows).
• Using native async mechanisms ensures scalability as Node.js relies on the OS kernel instead of blocking the main thread.

const crypto = require('crypto');

console.log("Start pbkdf2 experiments...");

const start = Date.now();
crypto.pbkdf2('password', 'salt', 100000, 64, 'sha512', () => {
  console.log('1:', Date.now() - start);
});

crypto.pbkdf2('password', 'salt', 100000, 64, 'sha512', () => {
  console.log('2:', Date.now() - start);
});