Summary

Create a cookbook-style guide for performance optimization covering SIMD aggregation, lock-free queues, memory pools, hot path helpers, and thread-local buffering.

Parent Issue

Part of: [EPIC] docs: Address documentation gaps across all ecosystem systems (kcenon/common_system#325)

Background (Why)

monitoring_system includes several optimization components that are undocumented:

• SIMD aggregator for vectorized metric computation
• Lock-free queue for high-throughput event passing
• Memory pool for reduced allocation overhead
• Hot path helper for critical path optimization
• Thread-local buffer for per-thread metric accumulation

While docs/performance/PERFORMANCE_TUNING.md exists, it doesn't cover these internal optimization mechanisms.

Source files:

• include/kcenon/monitoring/optimization/simd_aggregator.h — SIMD vectorized aggregation
• include/kcenon/monitoring/optimization/lockfree_queue.h — Lock-free event queue
• include/kcenon/monitoring/optimization/memory_pool.h — Pool-based allocation
• include/kcenon/monitoring/utils/hot_path_helper.h — Hot path optimization
• include/kcenon/monitoring/core/thread_local_buffer.h — Thread-local metric buffering

Scope (What)

Create docs/guides/PERFORMANCE_COOKBOOK.md covering:

1. SIMD Aggregator

• Supported SIMD instruction sets (AVX2, NEON)
• When SIMD aggregation is beneficial
• Configuration and fallback behavior

2. Lock-Free Queue

• Queue design and guarantees
• Producer-consumer patterns
• Sizing and memory considerations
• Comparison with mutex-based alternatives

3. Memory Pool

• Pool sizing strategies
• Pre-allocation patterns
• Memory fragmentation avoidance

4. Hot Path Optimization

• What constitutes a hot path in monitoring
• Branch prediction hints
• Cache-friendly data layouts

5. Thread-Local Buffering

• Per-thread metric accumulation
• Buffer flush strategies
• Reducing contention

6. Tuning Recipes

• Recipe: Maximum throughput (>1M metrics/sec)
• Recipe: Minimum latency (<100ns per metric)
• Recipe: Minimum memory (<10MB footprint)
• Recipe: Balanced production configuration

Acceptance Criteria

• All 5 optimization components documented
• SIMD usage patterns explained
• Lock-free queue tuning guide
• At least 4 tuning recipes
• Before/after performance comparisons