Wayland is rapidly becoming the preferred display server for Linux desktops, offering smoother performance and improved security compared to its predecessor, X11. But not all applications are created equal. Some are fully Wayland-native, taking advantage of Wayland's features, while others are still using X11 compatibility layers. Knowing whether an application is truly Wayland-native can be crucial for troubleshooting performance issues or understanding its behavior. This post shows you a slick way to do just that using the powerful xprop command.
Understanding Wayland and X11 Compatibility
Before diving into the xprop trick, let's quickly recap the difference. Wayland is a modern display server designed from the ground up for compositors. It offers direct access to the graphics hardware, resulting in better performance and smoother animations. X11, on the other hand, is the older, more established system, and many applications still rely on it. Often, applications that aren't Wayland-native will run within an Xwayland compatibility layer, which bridges the gap between X11 and Wayland. This compatibility layer, while helpful, can introduce performance overhead.
The xprop Magic: Unveiling the Wayland Identity
The command-line utility xprop is a powerful tool for inspecting window properties. We can leverage it to discreetly determine if an application is running natively under Wayland or through Xwayland. Here's how:
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Identify your target application window. Make sure the application you want to check is running.
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Run
xpropwith the window selected. Click on the window of the application you're investigating. Then, open a terminal and run the following command:xprop | grep WM_CLASS -
Interpret the results. The output will show a line similar to this:
WM_CLASS(STRING) = "myapp", "My Application"This line displays the window's class and name. However, we're not interested in this directly! The crucial information is hidden a bit deeper.
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(The clever part!) Run
xpropagain, focusing on the window's parent: Wayland-native windows have a parent window associated with them. To locate this parent, you will have to utilize your window manager's properties. Some window managers like Sway will list the parent ID directly. Others may need additional research to find the window ID of the parent window. Once you've located the parent window's ID, run the following:xprop -id <parent_window_id> | grep _NET_WM_PIDReplace
<parent_window_id>with the actual ID number of the parent window of your application. -
Analyze the _NET_WM_PID output: If the output shows a process ID (PID) associated with the Wayland compositor (like
waylandor a similar process on your system), it's a strong indication that the application is Wayland-native. If, instead, you see a PID associated with Xwayland, then the application is using the compatibility layer.
Troubleshooting and Advanced Usage
If you encounter issues, ensure you have xprop installed. The exact method depends on your distribution (e.g., sudo apt-get install x11-utils on Debian/Ubuntu). Also, remember that the window ID and parent window id may vary depending on your window manager and the application structure. Always carefully check the window ID to ensure you're targeting the correct window. Experiment with different applications and observe the variations in the _NET_WM_PID to gain a deeper understanding of the results.
Conclusion
This technique provides a reliable, albeit slightly more advanced, method for determining whether an application is Wayland-native. By combining xprop with a careful examination of parent window properties, you can get a clearer picture of your application's interaction with the Wayland display server. This knowledge can be invaluable for optimizing performance and troubleshooting issues in your Wayland-based desktop environment.
