worldgen-profiling

Fabric mod that adds custom JFR events to profile world generation

Creating a JFR report

1. Launch Minecraft 1.18 with Fabric.
2. Download the latest release and add it in the mods folder.
3. Start by running the /jfr start command and generate new terrain.
4. Run /jfr stop. This will create a file at .minecraft/debug/client-*.jfr.

Analyzing the JFR report

1. Download and install the JDK Mission Control tool.
2. In Mission Control, navigate to File > Open File... and select the JFR report.
   
3. Select the Even Browser Page in the Outline.
   
4. Find the Minecraft > World Generation > Feature Placement event type, and select it.
5. Create a new page with just this event type.
   
6. Because the JFR file has an event for each feature placement per chunk, it is useful to group events.
   
7. In this view, you can show average and total durations. It is now really easy to see which features are the bottlenecks.