flamegraphs

Flamegraphs are a visualization technique used for analyzing the performance of software. They represent a hierarchical view of profiled data, often generated by performance profiling tools. The width of each bar in a flamegraph corresponds to the time spent in a particular function or code path. Wider bars indicate functions that consume more time. The stacking of bars visually represents the call stack. A wider bar at the bottom of a stack signifies a function that was called by functions higher up in the stack.

The primary purpose of a flamegraph is to quickly identify performance bottlenecks. By observing the widest bars, developers can pinpoint the functions or code sections that are consuming the most CPU time. The visualization's layout makes it easy to understand the relationship between different functions and how they contribute to the overall execution time. This hierarchical representation allows for a deep dive into performance issues, from high-level system calls down to specific lines of code.

Flamegraphs are generated by collecting profiling data, which typically involves sampling the program's call stack at regular intervals. Tools then process this raw data to create the flamegraph image. The visualization is particularly effective for understanding complex, multi-threaded applications where performance issues can be distributed across various parts of the system. They are a valuable tool in the software development lifecycle for performance optimization and debugging.