Consider two different implementations M1 M2 of the same in

Consider two different implementations, M1 & M2, of the same instruction set. There are three classes of instructions (A, B, & C) in the instruction set. M1 has a clock rate of 80 MHz & M2 has a clock rate of 100 MHz. The average number of cycles for each instruction class & their frequencies (for a typical program) are as follows: see picture.
1) Calculate the average CPI for each machine, M1, & M2.

Solution

cpi means clocks per instruction

average cpi can be obtained by multiplying the cpi with frequency with their respective machines

Avg CPI for M1 is defined as below:

average clocks per Instruction for M1 = (60/100)* 1 + (30/100)*2 + (10/100)*4
= 1.6

Avg CPI for M2 is defined as below:

average clocks per Instruction for M2 = (60/100)*2 + (30/100)*3 + (10/100)*4
= 2.5