ios-performance

iOS Performance Router

You MUST use this skill for ANY performance issue including memory leaks, slow execution, battery drain, or profiling.

When to Use

Use this router when:

• App feels slow or laggy
• Memory usage grows over time
• Battery drains quickly
• Device gets hot during use
• High energy usage in Battery Settings
• Diagnosing performance with Instruments
• Memory leaks or retain cycles
• App crashes with memory warnings

Routing Logic

Memory Issues

Memory leaks (Swift) → /skill memory-debugging

• Systematic leak diagnosis
• 5 common leak patterns
• Instruments workflows
• deinit not called

Memory leaks (Objective-C blocks) → /skill objc-block-retain-cycles

• Block retain cycles
• Weak-strong pattern
• Network callback leaks

Performance Profiling

Performance profiling → /skill performance-profiling

• Time Profiler (CPU)
• Allocations (memory growth)
• Core Data profiling (N+1 queries)
• Decision trees for tool selection

Energy Issues

Battery drain, high energy → /skill energy

• Power Profiler workflow
• Subsystem diagnosis (CPU/GPU/Network/Location/Display)
• Anti-pattern fixes
• Background execution optimization

Symptom-based diagnosis → /skill energy-diag

• "App at top of Battery Settings"
• "Device gets hot"
• "Background battery drain"
• Time-cost analysis for each path

API reference with code → /skill energy-ref

• Complete WWDC code examples
• Timer, network, location efficiency
• BGContinuedProcessingTask (iOS 26)
• MetricKit setup

Decision Tree

User reports performance issue
  ├─ Memory?
  │  ├─ Swift code? → memory-debugging
  │  └─ Objective-C blocks? → objc-block-retain-cycles
  │
  ├─ Energy/Battery?
  │  ├─ Know the symptom? → energy-diag
  │  ├─ Need API reference? → energy-ref
  │  └─ General battery drain? → energy
  │
  ├─ Want to profile?
  │  └─ YES → performance-profiling
  │
  └─ General slow/lag? → performance-profiling

Critical Patterns

Memory Debugging (memory-debugging):

• 6 leak patterns: timers, observers, closures, delegates, view callbacks, PhotoKit
• Instruments workflows
• Leak vs caching distinction

Performance Profiling (performance-profiling):

• Time Profiler for CPU bottlenecks
• Allocations for memory growth
• Core Data SQL logging for N+1 queries
• Self Time vs Total Time

Energy Optimization (energy):

• Power Profiler subsystem diagnosis
• 8 anti-patterns: timers, polling, location, animations, background, network, GPU, disk
• Audit checklists by subsystem
• Pressure scenarios for deadline resistance

Example Invocations

User: "My app's memory usage keeps growing" → Invoke: /skill memory-debugging

User: "I have a memory leak but deinit isn't being called" → Invoke: /skill memory-debugging

User: "My app feels slow, where do I start?" → Invoke: /skill performance-profiling

User: "My Objective-C block callback is leaking" → Invoke: /skill objc-block-retain-cycles

User: "My app drains battery quickly" → Invoke: /skill energy

User: "Users say the device gets hot when using my app" → Invoke: /skill energy-diag

User: "What's the best way to implement location tracking efficiently?" → Invoke: /skill energy-ref