Mobile Perf Profiler

Diagnose mobile performance from measured evidence, fix the largest cost, and re-measure - never guess. The costly failure is folklore optimization: weeks spent caching and micro-tuning paths the profiler would show are cheap, while the one 40ms bind on the scroll path ships untouched.

Operating procedure

Step 1: Gather inputs

1. The exact symptom, named precisely: jank while scrolling a specific list, jank on first frame of a screen, slow cold start, or memory that climbs. "The app feels slow" is not a symptom yet - reproduce until it is one.
2. A representative device: a real mid-tier phone from the install base, not the developer's flagship and never a simulator/emulator.
3. A release or profile build. Debug builds misreport timing by integer factors.
4. The display refresh rate of target devices - 60Hz means a 16.6ms frame budget, 120Hz means 8.3ms.
5. Field data access: Play Console Android vitals, Xcode Organizer / MetricKit. If available, this decides which symptom is worth the trace before any local work.

Step 2: Work the evidence ladder, cheapest first

Escalate only when the cheaper rung has not localized the cause: