How to use Chrome DevTools for performance analysis?

Chrome DevTools Performance Analysis Tools

Chrome DevTools provides powerful performance analysis tools to help developers identify and optimize performance bottlenecks.

Main Performance Panels

1. Performance Panel

   • Records performance data during page runtime
   • Displays FPS, CPU usage, memory usage
   • Analyzes script execution, rendering, layout timing
   • Identifies long tasks and main thread blocking

2. Network Panel

   • View all network requests
   • Analyze request timeline
   • Check request size and response time
   • Identify slow requests and resource loading issues

3. Memory Panel

   • Monitor memory usage
   • Detect memory leaks
   • Analyze heap snapshots
   • Track memory allocation

4. Lighthouse Panel

   • Comprehensive performance score
   • Provides optimization suggestions
   • Checks accessibility, SEO, best practices
   • Generates performance reports

Performance Metrics

• FCP (First Contentful Paint): Time for first content to be painted
• LCP (Largest Contentful Paint): Time for largest content to be painted
• FID (First Input Delay): Delay before first user input
• CLS (Cumulative Layout Shift): Cumulative layout shift
• TTI (Time to Interactive): Time when page becomes interactive

Optimization Recommendations

1. Reduce JavaScript Execution Time

   • Code splitting and lazy loading
   • Use Web Workers for complex calculations
   • Avoid long tasks

2. Optimize Resource Loading

   • Compress and merge resources
   • Use CDN acceleration
   • Preload critical resources

3. Improve Rendering Performance

   • Reduce DOM operations
   • Use CSS3 animations
   • Optimize image loading

Usage Tips

• Use Performance panel to record page interactions
• Compare performance data before and after optimization
• Focus on core metrics related to user experience
• Continuously monitor and optimize performance