In this web content, the author discusses their discovery of the /jfr command in Minecraft, which allows for the creation of custom Java Flight Recorder (JFR) events. They explain the process of using the /jfr command, including the need for OP privileges and the recording and stopping of events. The JFR files are stored in the debug folder of the server’s working directory, and can be viewed with JFR viewers such as JMC or the author’s IntelliJ JFR plugin. The author then explores the event specification and provides an example of the ChunkGeneration event. They note that these custom events have been discovered by other OpenJDK developers, such as Erik Gahlin. The author concludes by emphasizing the value of custom events in Minecraft and their usefulness in improving application performance.
https://mostlynerdless.de/blog/2023/11/27/custom-events-in-the-blocky-world-using-jfr-in-minecraft/