Chapter 2, Problem 2.46.1E

Explanation of Solution

“No”, the given design is not a good choice because the execution time is more to compute the problem it will slow down the computer.

Explanation:

The Cycle Per Instruction (CPI) can be calculated using the following formula:

$\text{CPI}\text{=}\frac{\text{clock}\text{rate}\text{×}\text{CPU}\text{time}}{\text{instruction}\text{count}}$

Here, clock rates = $\text{10, 1, 3}$

CPI times = $\text{300, 500, 100}$

Instruction count = $\text{300 + 500 + 100}$

          = $\text{900}$

$\begin{array}{l}\text{Initial CPI = 10}\times \left(\frac{300}{900}\right)+\text{1}\times \left(\frac{500}{900}\right)+3\times \left(\frac{100}{900}\right)\\ \text{ = }\frac{30}{9}+\frac{5}{9}+\frac{3}{9}\\ \text{}\text{ = }\frac{38}{9}\\ \text{ = 4}\text{.22}\end{array}$

$\begin{array}{l}\text{New number of arithmetic instruction = 0}\end{array}$