Axiom Performance

# Performance

**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)** → See skills/memory-debugging.md
- Systematic leak diagnosis
- 5 common leak patterns
- Instruments workflows
- deinit not called

**Memory leak scan** → Launch `memory-auditor` agent or `/axiom:audit memory` (5-phase semantic audit: maps resource ownership, detects 6 leak patterns, reasons about missing cleanup, correlates compound risks, scores lifecycle health)

**Memory leaks (Objective-C blocks)** → See skills/objc-block-retain-cycles.md
- Block retain cycles
- Weak-strong pattern
- Network callback leaks

### Performance Profiling

**Performance profiling (GUI)** → See skills/performance-profiling.md
- Time Profiler (CPU)
- Allocations (memory growth)
- Core Data profiling (N+1 queries)
- Decision trees for tool selection

**Automated profiling (CLI)** → See skills/xctrace-ref.md
- Headless xctrace profiling
- CI/CD integration patterns
- Command-line trace recording
- Programmatic trace analysis

**Run automated profile** → Use `performance-profiler` agent or `/axiom:profile`
- Records trace via xctrace
- Exports and analyzes data
- Reports findings with severity

**Compare two traces / detect regressions** → See skills/trace-comparison.md or `/axiom:compare-traces`
- Did this change slow down a hot path? Function-level CPU-share deltas
- CI gating with `xcprof compare --fail-on-regression` (non-zero exit)
- Regressions vs improvements, severity ranking, exit-code semantics

### Hang/Freeze Issues

**App hangs or freezes** → See skills/hang-diagnostics.md
- UI unresponsive for >1 second
- Main thread blocked (busy or waiting)
- Decision tree: busy vs blocked diagnosis
- Time Profiler vs System Trace selection
- 8 common hang patterns with fixes
- Watchdog terminations

**Corpus/aggregate hang triage (Sentry, ASC)** → `axiom-shipping (skills/production-triage.md)` + `triage-analyzer` agent
- Multiple grouped hang reports from an aggregator, not a single .ips file
- Classify `anr_idle_runloop` vs `anr_main_thread_block` across the corpus
- Flag suspension/idle-runloop false-positives (the #1 hang by user count is often noise)
- Cluster into root-cause families and rank by impact

### App Launch

**Slow app launch** → See skills/app-launch.md
- Slow first frame, frozen first screen, launch regression in Organizer
- Launch-phase model (pre-main / main→first frame / extended launch)
- Cold vs warm vs hot/resume vs notification launch — how to reproduce each
- App Launch instrument workflow, `dyld Activity`, measurement hygiene
- Pre-main fixes (frameworks, `+load`, mergeable libraries), main-thread deferral, priority inversion
- `XCTApplicationLaunchMetric` regression test, `MXAppLaunchMetric` field histograms, custom "app is interactive" signpost
- Push-notification launch path (tap→first pixel / tap→interactive targets)

### Energy Issues

**Battery drain, high energy** → See skills/energy.md
- Power Profiler workflow
- Subsystem diagnosis (CPU/GPU/Network/Location/Display)
- Anti-pattern fixes
- Background execution optimization

**Symptom-based diagnosis** → See skills/energy-diag.md
- "App at top of Battery Settings"
- "Device gets hot"
- "Background battery drain"
- Time-cost analysis for each path

**API reference with code** → See skills/energy-ref.md
- Complete WWDC code examples
- T