CPU time, also known as processor time or execution time, refers to the amount of time that a central processing unit (CPU) spends to execute a specific task. It is a crucial metric to understand and measure the performance and efficiency of a processor., CPU time is an indication of how much processing time a process has used since it has started (Windows defines it the same way, as documented on Microsoft Learn in this article for Windows 2000). It is basically calculated by: CPU Time of Process = Process Uptime * CPU Utilization of Process., CPU time refers to the actual time a CPU spends processing data for a program, as opposed to waiting for other operations such as input/output processes. It is a crucial metric that can be indicative of a program’s efficiency and the overall performance of a system., The CPU time is the time that the process is using the CPU - converting it to a percentage is done by dividing by the amount of real time that's passed. So, if I have a process that uses 1 second of CPU time over a period of 2 seconds, it's using 50% of a CPU., We’ll explore what CPU time is, how to calculate CPU, and why it matters, especially for performance testers and engineers. You’ll learn to break down the simple formula, understand each component in real-life projects., CPU time can be divided into user CPU time (CPU time spent in the program, which includes library routines) and system CPU time (CPU time spent in the OS performing tasks for the program). Since time is the only reliable measure of performance, it should be included in any measure of performance..