Question

Consider a processor that has a CPI of 1 for all instructions besides loads. Loads are 33% of the instructions and have the AMAT calculated above. What is the average CPI of the processor? Assume the processor does not support OOO and that a load stalls the pipeline until it is served. Provide the formula to compute your result as well as the final result.

AMAT was calculated as 10 Cycles

Answer 1

The average CPI of the processor, considering that loads are 33% of the instructions and have an AMAT of 10 cycles, is computed as 3.97.

Step-by-step explanation:

The student is asking about the average Cycles Per Instruction (CPI) for a processor where loads represent 33% of the instructions and have an Average Memory Access Time (AMAT) of 10 cycles. In this processor, non-load instructions have a CPI of 1.

The formula to calculate the average CPI of the processor is:

`CPI_(average) = CPI_(non-load) \(*\) (1 - fraction_(load)) + CPI_(load) \(*\) fraction_(load)`

Using the provided data, we get:

`CPI_(average) = 1 \(*\) (1 - 0.33) + 10 \(*\) 0.33`

`CPI_(average) = 1 \(*\) 0.67 + 10 \(*\) 0.33`

`CPI_(average) = 0.67 + 3.3`

`CPI_(average) = 3.97`