1. Suppose you wish to run a program P with 21.5 x 10 ⁹ instructions on a 6 GHz machine with a CPI of 0.90. What is the expected CPU time to execute this program on this machine?

2. Consider two different implementations, I1 and I2, of the same instruction set. There are three classes of instructions (A, B, and C) in the instruction set. I1 has a clock rate of 6 GHz, and I2 has a clock rate of 5 GHz. The average number of cycles for each instruction class on I1 and I2 is given in the following table:

Class	CPI on I1	CPI on I2	C1 Usage	C2 Usage	C3 Usage
A	4	3	45%	30%	35%
B	2	4	35%	40%	25%
C	3	2	20%	30%	40%

The table also contains a summary of average proportion of instruction classes generated by three different compilers, C1, C2, and C3. Assume that each compiler uses the same number of instructions for a given program but that the instruction mix is as described in the table.

a). Using C1, compute the average CPI for each of I1 and I2. Then compute the speed, that is the average number of instructions per second for each of I1 and I2. Then decide which one is faster than the other? and in what ratio?

b). Using C2, compute the average CPI for each of I1 and I2. Then compute the speed, that is the average number of instructions per second for each of I1 and I2. Then decide which one is faster than the other? and in what ratio?

c) Using C3, compute the average CPI for each of I1 and I2. Then compute the speed, that is the average number of instructions per second for each of I1 and I2. Then decide which one is faster than the other? and in what ratio?

d). If you purchased I1, which compiler has a better performance than others?

e). If you purchased I2, which compiler has a better performance than others?

f). Which combination of computer and compiler has the best performance if all other criteria were identical, including cost?