Performance Profiling Skill

Optimization Golden Rule

"Don't optimize without a baseline." Always measure -> change -> measure.

Critical Metrics (The 4 Golden Signals)

1. Latency: Time it takes to serve a request. (p50, p95, p99)
2. Traffic: Demand on your system (req/sec).
3. Errors: Rate of requests that fail.
4. Saturation: How "full" your service is (CPU/Memory usage).

Profiling Tools & Techniques