Trace Capture¶

Capture Perfetto traces from Android devices via adb.

Prerequisites¶

adb must be in your PATH
Device connected via USB or wireless debugging
Only one device connected (or use ANDROID_SERIAL env var)

Commands¶

trace start¶

Start a trace capture session.

# Default: 10 second capture
perfetto-cli trace start

# Custom duration
perfetto-cli trace start --duration 30s

# Custom buffer size
perfetto-cli trace start --buffer-size 64mb

Options:

Option	Description	Default
`--duration <time>`	Capture duration (e.g., `10s`, `1m`)	10s
`--buffer-size <size>`	Ring buffer size (e.g., `32mb`, `64mb`)	32mb

trace stop¶

Stop an active capture and pull the trace file.

perfetto-cli trace stop

trace run¶

One-shot capture: start → wait → stop → pull.

perfetto-cli trace run --duration 15s -o ./traces

Options:

Option	Description	Default
`--duration <time>`	Capture duration	10s
`-o, --output <dir>`	Output directory for trace file	Current directory

Workflow¶

# 1. Start your app and reproduce the issue
# 2. Capture a trace
perfetto-cli trace run --duration 15s -o ./traces

# 3. Analyze the trace
perfetto-cli -t ./traces/*.perfetto-trace -p com.example.app frame jank

Tips¶

Use longer durations for intermittent issues
Increase buffer size for high-frequency traces to avoid data loss
The run command is best for scripted/CI workflows