spark
A performance profiler for Minecraft clients, servers, and proxies
...It helps developers and server administrators analyze performance issues such as lag, high CPU usage, and memory bottlenecks. The plugin collects statistical information about the server’s execution and generates detailed profiling data that can be used to identify inefficient code or problematic plugins. spark includes tools for CPU profiling, memory inspection, and monitoring server health metrics over time. The profiling data is typically visualized through an online viewer that displays call graphs and flame graphs to help users interpret performance results. Because it is lightweight and designed to run in production environments, administrators can safely use it on live servers to diagnose performance issues without significant overhead.