Question

Suppose the Machine cycle was broken into the following
"mini-steps": Fetch instruction , Decode the instruction opcode (operation) , Calculate effective address of operands(data), Fetch operands, Execute instruction & store result. Then the question arises is that the instruction(task) which takes five cycles to execute in a non pipelined CPU. In a CPU with a five stage pipeline, that instruction still takes five cycles to execute, so how can we say the pipeline speeds up the execution of the program as compared to non-pipelined? justify your answer

Answer 1

Explanation:

In non pipelined processor, the clock cycle time is calculated by taking the execution time of each step and then adding those up. This addition always generates a higher cycle time.

Now in case of pipelined processor, the cycle time is calculated by considering the execution time of all steps and then picking out the least time.

Hence the clock cycle time of pipelined processor would always be less than non pipelined processor incase of multiple steps