Question

To perform a task a non-pipeline system takes 50 nsec. The same task can be performed in a pipeline system with 6 segments and pipeline cycle time of 10 nsec. In pipeline system 20% of tasks incur 3 stall cycles. The speed up of pipeline is _______.

Answer 1

option (b)

$\text{Non-pipeline time}=50nsec\text{pipeline CPI = 0.8 * 1 + 0.2 * (1 + 3)}=1.6\text{pipeline time = 1.6*10 nsec}\text{= 16 nsec}\text{Speed up}=\frac{\text{non-pipeline time}}{\text{pipeline time}}=\frac{50}{16}=3.125$