Pipelining/Problem 2

We have a single stage, non-pipelined machine and a pipelined machine with 5 pipeline stages. The cycle time of the former is 5ns and the latter is 1ns.

a. Assuming no stalls, what is the speedup of the pipelined machine over the single stage machine?

b. Given the pipeline stalls 1 cycle for 40% of the instructions, what is the speed up now?


a. Speed up = 5ns/1ns = 5

b.Pipeline loses 1 cycle 40% of the time. CPI is now 1.4. Speed up = (1 CPI * 5ns) / (1.4 CPI * 1ns) = 3.58