Worldgen profiling

## Creating a JFR report 1. Launch Minecraft with (https://fabricmc.net/use/). 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 (https://adoptopenjdk.net/jmc) tool. 2. In Mission Control, navigate to `File > Open File...` and select the JFR report. !(https://user-images.githubusercontent.com/17352009/144514425-a71842e1-366c-4678-9465-beaed0a9e3af.png) 3. Select the `Even Browser` Page in the Outline. !(https://user-images.githubusercontent.com/17352009/144514569-9e50506b-1acf-45c5-aad5-d3427158ce6a.png) 4. Find the `Minecraft > World Generation > Feature Placement` event type, and select it. 5. Create a new page with just this event type. !(https://user-images.githubusercontent.com/17352009/144514802-ca24340e-84f2-4213-9465-4a8fba4d9cf6.png) 6. Because the JFR file has an event for each feature placement per chunk, it is useful to group events. !(https://user-images.githubusercontent.com/17352009/144514943-a6069315-49ad-4db7-88d7-6f1b10738361.png) !(https://user-images.githubusercontent.com/17352009/144515033-db20ffff-3171-43b1-b979-57164ea2007a.png) 7. In this view, you can show average and total durations. It is now really easy to see which features are the bottlenecks. !(https://user-images.githubusercontent.com/17352009/144515176-afe85862-ecd1-4e36-b5c9-9baf343a230c.png) !(https://user-images.githubusercontent.com/17352009/144515232-91e7f84f-c535-406f-936a-6d0973fefb71.png)