Performance Profiler

# Performance Profiler **Tier:** POWERFUL **Category:** Engineering **Domain:** Performance Engineering --- ## Overview Systematic performance profiling for Node.js, Python, and Go applications. Identifies CPU, memory, and I/O bottlenecks; generates flamegraphs; analyzes bundle sizes; optimizes database queries; detects memory leaks; and runs load tests with k6 and Artillery. Always measures before and after. ## Core Capabilities - **CPU profiling** — flamegraphs for Node.js, py-spy for Python, pprof for Go - **Memory profiling** — heap snapshots, leak detection, GC pressure - **Bundle analysis** — webpack-bundle-analyzer, Next.js bundle analyzer - **Database optimization** — EXPLAIN ANALYZE, slow query log, N+1 detection - **Load testing** — k6 scripts, Artillery scenarios, ramp-up patterns - **Before/after measurement** — establish baseline, profile, optimize, verify --- ## When to Use - App is slow and you don't know where the bottleneck is - P99 latency exceeds SLA before a release - Memory usage grows over time (suspected leak) - Bundle size increased after adding dependencies - Preparing for a traffic spike (load test before launch) - Database queries taking >100ms --- ## Quick Start ```bash # Analyze a project for performance risk indicators python3 scripts/performance_profiler.py /path/to/project # JSON output for CI integration python3 scripts/performance_profiler.py /path/to/project --json # Custom large-file threshold python3 scripts/performance_profiler.py /path/to/project --large-file-threshold-kb 256 ``` --- ## Golden Rule: Measure First ```bash # Establish baseline BEFORE any optimization # Record: P50, P95, P99 latency | RPS | error rate | memory usage # Wrong: "I think the N+1 query is slow, let me fix it" # Right: Profile → confirm bottleneck → fix → measure again → verify improvement ``` --- ## Node.js Profiling → See references/profiling-recipes.md for details ## References - [references/profiling-recipes.md](references/profiling-recipes.md) — Node.js/Python/Go profiling commands, flamegraph generation, heap snapshots - [references/optimization-playbook.md](references/optimization-playbook.md) — before/after measurement template, quick-win optimization checklist (DB/Node/bundle/API), common pitfalls, best practices