- Qt 6.12
- Qt Qml
- Prototyping, Debugging and Profiling QML Applications
- Profiling QML Applications
- Qt 6.12.0 Reference Documentation

Debugging QML Applications ◦ Qt Qml Tooling

# Profiling QML Applications

## QML Profiler

With the QML Profiler you can analyze your QML code for performance issues. The profiler is part of both Qt Creator and Qt Design Studio. The best way to use it is to utilize Qt Creator or Qt Design Studio defaults for build and run settings.

If you are building or running manually, in order to use the QML Profiler, you need to enable the QML debugging infrastructure.

## Using the command line qmlprofiler tool

Qt provides the qmlprofiler command line tool to capture profiling data in a file. The file can later be loaded into Qt Creator or Qt Design Studio for analysis. It connects to the application using the debugging protocol.

To run this tool, after starting the application with the QML debugging infrastructure enabled, enter the following command:

`qmlprofiler -p <port> -attach <ip address>`

It is advisable to use the `services` argument to `-qmljsdebugger` in order to limit the debug infrastructure to only the services required. These are typically `CanvasFrameRate`, `EngineControl`, and `DebugMessages`. Having other services enabled may influence the profiling results.

Debugging QML Applications ◦ Qt Qml Tooling