How does the CPU usage occur during synchronous operations?

When performing synchronous operations, the processor executes each instruction sequentially, blocking the execution of the next until the current one is completed. This means that until the operation finishes, the processor does not switch to other tasks within this thread.

For example, if a program reads a file synchronously, the processor will wait for the read operation to complete, not performing other tasks in parallel within this thread. In multitasking systems, the processor can switch between threads, but within a single synchronous thread, execution is strictly sequential.

Thus, during synchronous execution, the processor is busy with the current task until it is finished, which can lead to idle time while waiting for input/output or other long operations.