Native App Performance (CLI-only)

Goal: record Time Profiler via xctrace, extract samples, symbolicate, and propose hotspots without opening Instruments.

Quick start (CLI) Record Time Profiler (attach):

Start app yourself, then attach

xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --attach

Record Time Profiler (launch): xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --launch -- /path/App.app/Contents/MacOS/App

Extract time samples: scripts/extract_time_samples.py --trace /tmp/App.trace --output /tmp/time-sample.xml

Get load address for symbolication:

While app is running

vmmap | rg -m1 "__TEXT" -n

Symbolicate + rank hotspots: scripts/top_hotspots.py --samples /tmp/time-sample.xml \ --binary /path/App.app/Contents/MacOS/App \ --load-address 0x100000000 --top 30

Workflow notes Always confirm you’re profiling the correct binary (local build vs /Applications). Prefer direct binary path for --launch. Ensure you trigger the slow path during capture (menu open/close, refresh, etc.). If stacks are empty, capture longer or avoid idle sections. xcrun xctrace help record and xcrun xctrace help export show correct flags. Included scripts scripts/record_time_profiler.sh: record via attach or launch. scripts/extract_time_samples.py: export time-sample XML from a trace. scripts/top_hotspots.py: symbolicate and rank top app frames. Gotchas ASLR means you must use the runtime __TEXT load address from vmmap. If using a new build, update the --binary path; symbols must match the trace. CLI-only flow: no need to open Instruments if stacks are symbolicated via atos.