performance

Performance Optimization Skill

Reusable workflow extracted from otto-performance-optimizer expertise.

Systematically identify and eliminate performance bottlenecks through data-driven profiling, algorithmic optimization, and infrastructure tuning.

When to Use

Performance degradation | Pre-release validation | Scalability planning | High-load optimization | Cost optimization | Database tuning | Frontend Core Web Vitals | Infrastructure right-sizing

Workflow

| Step | Actions | |------|---------| | 1. Define Goals | Specific targets (P95 < 200ms), throughput (req/sec), resource efficiency, UX requirements, baseline | | 2. Baseline | Reproducible benchmarks, measure key metrics, representative workloads, document environment | | 3. Profile | CPU (hot paths), Memory (leaks, GC), I/O (disk/network), Database (EXPLAIN), Frontend (Lighthouse) | | 4. Bottlenecks | Analyze profiling data, root causes vs symptoms, quantify impact, prioritize by impact/effort | | 5. Prioritize | Quick Wins (high/low), Strategic (high/med), Incremental (med/low), Deferred (low/high) | | 6. Implement | Incremental changes, measure independently, before/after metrics, verify no regressions | | 7. Validate | Compare vs baseline/goals, load tests at scale, edge cases, resource utilization, cost | | 8. Monitor | Performance dashboards, degradation alerts, CI/CD tests, document decisions, review cadence |

Inputs

• Performance targets (latency, throughput, resources)
• Current metrics (baseline)
• Workload profile (traffic patterns, peak loads)
• Constraints (budget, timeline, trade-offs)
• Environment (production specs, infrastructure)

Outputs

• Profiling Report (flame graphs, bottlenecks)
• Optimization Roadmap (prioritized with impact)
• Before/After Benchmarks
• Capacity Plan
• Monitoring Setup (metrics, dashboards, alerts)
• Cost Analysis

Profiling Tools

| Category | Tools | |----------|-------| | CPU | Python: cProfile, py-spy • JS/Node: Chrome DevTools, clinic.js, 0x • C/C++: Instruments, perf, Valgrind • Java: JProfiler, JFR • Go: pprof | | Memory | Python: memory_profiler, tracemalloc • JS/Node: heap profiler • C/C++: Valgrind, ASan • Java: VisualVM • Go: pprof heap | | Database | PostgreSQL: EXPLAIN ANALYZE, pg_stat_statements • MySQL: EXPLAIN, slow log • MongoDB: explain() • Redis: SLOWLOG | | System | Linux: perf, eBPF, sysstat • macOS: Instruments, dtrace • Network: Wireshark, tcpdump |

Optimization Strategies

Algorithmic

• Complexity: O(n²) → O(n log n) → O(n)
• Data structures: Array vs Hash vs Tree
• Caching: Memoization, computed properties
• Lazy evaluation: Compute on demand
• Batch processing: Avoid N+1 queries

Database

• Query optimization: Rewrite inefficient queries
• Indexes: B-tree, hash, partial, covering
• Connection pooling: 2-10× CPU cores
• Batching: Combine queries
• Denormalization: Trade-off for reads
• Caching: Redis/Memcached for hot data

Frontend

• Core Web Vitals: LCP < 2.5s, FID < 100ms, CLS < 0.1
• Bundle: Code splitting, tree shaking, lazy loading
• Assets: Compression, WebP, responsive images
• Caching: Service workers, Cache-Control
• CDN: Geographic distribution, edge caching

Backend

• API: Reduce payload, compression
• Async: Queue long tasks
• Connection reuse: HTTP keep-alive, pooling
• Caching layers: App, CDN, DB
• Concurrency: async/await, workers

Infrastructure

• Auto-scaling: Horizontal/vertical policies
• Right-sizing: Match actual usage
• Load balancing: Distribute efficiently
• Geo-distribution: Multi-region
• Resource limits: Prevent exhaustion

Metrics Checklist

See [metrics-checklist.md](./metrics-checklist.md) for latency, throughput, resource, and UX metrics.

Example

Input: /api/users P95: 3.2s, target: <200ms

Steps:
1. Goal: P95 < 200ms, throughput 5x
2. Baseline: P95 = 3.2s, 50 req/sec
3. Profile: 80% in DB query, full table scan, no index
4. Bottleneck: Missing index, N+1 pattern
5. Prioritize: Add index (quick), fix N+1 (quick), cache (strategic)
6. Implement: CREATE INDEX, rewrite query, Redis (TTL: 5min)
7. Validate: P95 = 45ms (98.6% ↓), 400 req/sec (8x ↑), DB CPU 85% → 12%
8. Monitor: Grafana dashboard, alert if P95 > 200ms

Output: ✅ P95 = 45ms, ✅ 400 req/sec, ✅ $2,400/mo saved

Anti-Patterns

| Anti-Pattern | Fix | |--------------|-----| | Premature optimization | Profile first, then optimize | | Micro-optimizations | Focus on measurable user impact | | Benchmark gaming | Use production-like workloads | | Complexity creep | Balance performance vs maintainability | | Ignoring trade-offs | Document explicitly |

Performance Budget

## [Feature/Page]

### Targets
- P95: < [x]ms
- Throughput: > [x] req/sec
- Page Load: < [x]s
- Bundle: < [x]KB

### Current
- P95: [y]ms
- Status: ✅/❌

### Action
[Optimization plan if exceeded]

Related Agents

• otto-performance-optimizer - Full profiling expertise
• baccio-tech-architect - Architecture-level design
• dario-debugger - Performance bug investigation
• omri-data-scientist - ML inference optimization
• marco-devops-engineer - Infrastructure tuning

Engineering Fundamentals

• Observability: metrics, tracing for performance
• Load testing: validates peak load behavior
• Performance testing: measures vs baselines
• Stress testing: finds breaking points
• NFRs: SLAs defined upfront
• Parametrize: easy configuration tuning
• Log durations: critical paths
• Realistic load: not just happy-path