How do operating systems manage the allocation of CPU resources among multiple running processes?

Operating systems play a critical role in managing hardware resources for executing applications efficiently. One of the most important tasks is scheduling CPU time among various processes and threads to ensure optimal performance and system responsiveness. Operating systems use different scheduling algorithms and policies to determine which process gets to execute at any given time. The choice of scheduling algorithm can significantly impact system performance, especially in environments with a high volume of concurrent processes. Explore the mechanisms through which operating systems schedule processes, including considerations like process priority, fairness, and system throughput, and discuss examples of how these policies might differ between popular operating systems like Windows, Linux, and macOS.