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Performance CLI is installed as part of the Vega Developer Tools (VDT). To analyze app performance, you can use either the command palette in the Vega Studio extension or the Performance command-line interface (CLI).

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Prerequisites

  1. Install the Vega SDK.
  2. Verify if the Performance CLI is installed in your development environment:

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Help option

To explore options for all Performance CLI commands:
To get information about a specific command:
To see all options for the record command:

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Commonly used commands

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kepler exec perf record

Use the record command to start the Event Recording tool. This captures performance events for analysis. The command takes the following arguments:
  • --app-name - Specifies the app’s main interactive component name from manifest.toml
  • --recording-timeout - Sets the recording duration in seconds (default: 120s)
  • --device-serial-number - Sets the device serial number when you have multiple devices
  • --output-dir - Specifies the output directory path
  • --trace-categories - Specifies platform trace categories to enable during tracing. Default categories: app, graphics, ui, lifecycle, input, video, and webview
  • --enable-cpu-sched - Enables CPU scheduler event recording during tracing (disabled by default)
To record performance events for your app:
To record with a specific timeout:
To record with custom trace categories:
To record with CPU scheduler events enabled:

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kepler exec perf activity-monitor

Use the activity-monitor command to start the Activity Monitor tool. The command takes the following arguments:
  • --app-name - Specifies the app’s main interactive component name from manifest.toml
  • --record-cpu-profiling - Enables the JavaScript CPU Profiler during recording
  • --sdk-path - Specifies the installed Vega SDK path (required when using --record-cpu-profiling)
  • --sourcemap-file-path - Specifies the JavaScript source map path (required when using --record-cpu-profiling)
To monitor app activity:
To monitor with CPU profiling enabled:

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kepler exec perf memory-monitor

Use the memory-monitor command to start the Memory Monitor tool. The command takes the following arguments:
  • --app-name - Specifies the app’s main interactive component name from manifest.toml
  • --keplerscript-app - Specifies the app is a React Native-based app for Vega
  • --relative-gc-count - Shows Garbage Collection (GC) count as delta between current and previous GC count (available only with React Native-based apps)
To monitor app memory:
To monitor with relative garbage collection count for React Native apps:
To start and stop recording sessions: For Mac:
  1. Press s to start recording.
  2. Press s again to stop the recording.
If pressing s doesn’t work, press S and Return. For Linux:
  1. Press s to start recording.
  2. Press s again to stop the recording.
If pressing s doesn’t work, press S and Enter. Press q and Return, or q and Enter, to quit recording.

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kepler exec perf kpi-visualizer

Use the kpi-visualizer command to measure your app KPIs. The command takes the following arguments:
  • --app-name - Specifies the app’s main interactive component name from manifest.toml
  • --overridden-video-fps - Overrides the frames per second for video fluidity calculations during video playback
To measure app KPIs:
To override video FPS for video fluidity calculations:
Last modified on October 8, 2025