common-performance-engineering

name	common-performance-engineering
description	Universal standards for high-performance development. Use when optimizing, reducing latency, fixing memory leaks, profiling, or improving throughput. (triggers: **/*.ts, **/*.tsx, **/*.go, **/*.dart, **/*.java, **/*.kt, **/*.swift, **/*.py, performance, optimize, profile, scalability, latency, throughput, memory leak, bottleneck)

Performance Engineering Standards

Priority: P0 (CRITICAL)

🚀 Core Principles

• Efficiency by Design: Minimize resource consumption (CPU, Memory, Network) without sacrificing readability.
• Measure First: Never optimize without a baseline. Use profiling tools before and after changes.
• Scalability: Design systems to handle increased load by optimizing time and space complexity.

💾 Resource Management

• Memory Efficiency:
  • Avoid memory leaks: explicit cleanup of listeners, observers, and streams.
  • Optimize data structures: use the most efficient collection for the use case (e.g., Set for lookups, List for iteration).
  • Lazy Initialization: Initialize expensive objects only when needed.
• CPU Optimization:
  • Algorithm Complexity: Aim for $O(1)$ or $O(n)$ where possible; avoid $O(n^2)$ in critical paths.
  • Offload Work: Move heavy computations to background threads or workers.
  • Minimize Re-computation: Use memoization for pure, expensive functions.

🌐 Network & I/O

• Payload Reduction: Use efficient serialization (JSON minification, Protobuf) and compression.
• Batching: Group multiple small requests into single bulk operations.
• Caching Strategy:
  • Implement multi-level caching (Memory -> Storage -> Network).
  • Use appropriate TTL (Time To Live) and invalidation strategies.
• Non-blocking I/O: Always use asynchronous operations for file system and network access.

⚡ UI/UX Performance

• Minimize Main Thread Work: Keep animations and interactions fluid by keeping the main thread free.
• Virtualization: Use lazy loading or virtualization for long lists/large datasets.
• Tree Shaking: Ensure build tools remove unused code and dependencies.

📊 Monitoring & Testing

• Benchmarking: Write micro-benchmarks for performance-critical functions.
• SLIs/SLOs: Define Service Level Indicators (latency, throughput) and Objectives.
• Load Testing: Test system behavior under peak and stress conditions.

Anti-Patterns

• No premature optimization: Profile first, fix proven bottlenecks only.
• No N+1 queries: Always batch and paginate data-access operations.
• No synchronous I/O on main thread: Async all file/network access.

References

• Performance Examples — profiling patterns, benchmark setup