I am having trouble with the CPU, CPI, and MIPS. I have a few examples, but not

Question

I am having trouble with the CPU, CPI, and MIPS. I have a few examples, but not many. I would just like help getting started please.
1. [15 points] Consider two different implementations, M1 and M2, of the same instruction set. There are three classes of instructions (A, B, and C) in the instruction set. M1 has a clock rate of 80 MHz and M2 has a clock rate of 100 MHz. The average number of cycles for each instruction class and their frequencies (for a typical program) are as follows:Instruction Class Machine M1 – Cycles/Instruction Class
Instruction Class(A,B,C)
Machine M1-cycles/instruction class(1,2,4)
Machine M2-cycles/instruction class(2,3,4)
Frequency(60%,30%,10%)
(a) Calculate the average CPI for each machine, M1, and M2.
(b) Calculate the average MIPS ratings for each machine, M1 and M2.

Explanation / Answer

a)
CPI = Cycles per instruction
avg CPI for M1
= .6*1 + .3*2 + .1*4
= 1.6

avg CPI for M2
= .6*2 + .3*3 + .1*4
= 2.5

b)
MIPS = Million Instructions Per Second


MIPS M1 = (80 * 106 )/(1.6* 106)

= 80/1.6 = 50 MIPS

MIPS M2 = (100 * 106 )/(2.5* 106)

= 100/2.5 = 40 MIPS

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