Agent Skills: iOS Performance

iOS Performance

Priority: P0

Implementation Workflow

1. Profile with Instruments — Regularly use Allocations and Leaks to detect memory issues. Use Time Profiler for CPU stalls.
2. Reuse cells — Always use dequeueReusableCell and keep cellForRowAt lightweight.
3. Cache images — Use SDWebImage or Kingfisher for remote assets. AsyncImage lacks caching for lists.
4. Offload to background — Move parsing, encryption, and heavy computation off the Main thread using GCD or Tasks.
5. Enable strict warnings — Set SWIFT_TREAT_WARNINGS_AS_ERRORS in Release builds.
6. Run static analysis — Use Xcode's "Analyze" (Product > Analyze) to catch logic errors.

See background processing and cell reuse examples

Anti-Patterns

• ❌ Parsing/processing on Main thread — offload to background using Task.detached or GCD
• ❌ Redundant cache clears — let the system handle low-memory via applicationDidReceiveMemoryWarning
• ❌ Undetected retain cycles — use Leaks instrument frequently during development

References

• Profiling & Optimization