bun.sh/bench/stress/hot-reload-files/README.md

Hot Reload Files Stress Test

This is a stress test for Bun's hot reloading functionality, designed to test performance with a high number of interdependent files.

What It Does

• Generates 1000 interconnected TypeScript modules
• Each module imports 2 other modules
• Uses IPC (Inter-Process Communication) to detect reloads
• Performs 1,000 hot reloads and tracks memory usage
• Reports statistics about hot reload performance

Usage

./run-stress-test.sh

This will:

1. Generate 1000 interconnected modules
2. Run the stress test that performs 10,000 hot reloads
3. Report complete performance statistics

How The Test Works

The test utilizes Node.js's child_process fork API for communication:

1. The main process (stress-test.ts) creates a child process running Bun with hot reloading
2. The modules communicate with the parent process via IPC when they're reloaded
3. After detecting a successful reload, the parent modifies another file
4. This continues for 1,000 iterations
5. Memory usage is tracked throughout the process

Architecture

• generate.ts: Creates 1000 interconnected modules with IPC signaling
• stress-test.ts: Controls the test, forks Bun, and tracks metrics
• run-stress-test.sh: Script to run the entire test from scratch

Performance Metrics

The test reports:

• Total number of hot reloads completed
• Time taken to complete all reloads
• Average time per reload
• Initial and final RSS memory usage