A CPU profiler is a tool used to analyze the performance of a computer's central processing unit (CPU). It helps developers understand how efficiently their software is using the CPU by tracking which functions or processes consume the most processing time. This information is crucial for optimizing applications and improving overall performance. By identifying bottlenecks, a CPU profiler allows programmers to make informed decisions about code improvements. Common profiling techniques include sampling, where the profiler periodically checks the state of the CPU, and instrumentation, which involves adding code to measure performance directly. These insights lead to faster and more efficient software.