When is overhead nonexistent in executing processes?

Question

If I have 5 processes arrive at the CPU all at different times in a CPU Burst with shortest process next scheduling, would overhead only exist if, lets say process one finishes before the next process arrives? The overhead being the idletime of the CPU?

Answer 1

You should think about the number of cpus. If two processes are using the same cpu, they will compete and slow the overall finish time down. A cpu switching between different processes or threads can slow things down more than idle time. So I would keep it to one process at a time per CPU.