Instruments Trace Viewer

Workflow

1. Export Table of Contents

bash

xctrace export --input /path/to/recording.trace --toc

The TOC XML reveals available runs, schema names, and processes.

2. Query Specific Data

Extract tables using schema names from the TOC:

bash

xctrace export --input recording.trace \
  --xpath '/trace-toc/run[@number="1"]/data/table[@schema="time-sample"]' \
  --output samples.xml

Common schemas: time-sample, allocation, leak, os-signpost, http-transaction

3. Symbolicate if Needed

When stack traces show addresses instead of function names:

bash

xctrace symbolicate --input recording.trace --dsym /path/to/MyApp.dSYM

dSYM locations: ~/Library/Developer/Xcode/Archives/, DerivedData/<project>/Build/Products/

Essential Commands

Command	Purpose
`xctrace export --input <file> --toc`	List all tables and schemas
`xctrace export --input <file> --xpath '<expr>'`	Extract specific data
`xctrace export --input <file> --har --output <file>.har`	Export network data as HAR
`xctrace symbolicate --input <file> --dsym <path>`	Add symbol names to traces

TOC Structure

xml

<trace-toc>
  <run number="1">
    <data>
      <table schema="time-sample" />
      <table schema="allocation" />
    </data>
    <processes>
      <process name="MyApp" pid="12345">
        <binary name="MyApp" UUID="..." />
      </process>
    </processes>
  </run>
</trace-toc>

XPath Patterns

bash

# All data from a table
--xpath '/trace-toc/run[@number="1"]/data/table[@schema="<schema>"]'

# Process binaries
--xpath '/trace-toc/run[@number="1"]/processes/process[@name="MyApp"]/binary'

# All runs
--xpath '/trace-toc/run/data/table[@schema="time-sample"]'

Template-Specific References

Consult these for detailed XPath patterns and output interpretation:

•Time Profiler: references/time-profiler.md
•Allocations: references/allocations.md
•Leaks: references/leaks.md
•SwiftUI: references/swiftui.md
•App Launch: references/app-launch.md
•Network: references/network.md
•File Activity: references/file-activity.md
•Metal System Trace: references/metal-system-trace.md
•CPU Counters: references/cpu-counters.md
•Signposts & Points of Interest: references/signposts-poi.md

Troubleshooting

•Empty output: Schema may not exist—export TOC first to verify available schemas
•Unsymbolicated after symbolication: Verify dSYM UUID matches binary UUID with dwarfdump --uuid MyApp.dSYM
•XPath returns nothing: Check run number exists and schema name is case-sensitive exact match