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.

2) Calculate the average MIPS ratings for each machine, M1 & M2.
** Hint: MIPSrating = ClockRate/(CPI×10^6)

Solution

Answers:

a ) Calculate the average CPI for each machine M1 and M2

Answer:

For machine M1:

Clocks per instruction (CPI) = (60/100)*1 + (30/100)*2 + (10/100)*4

                                                      = 0.6 + 0.6 + 0.4

                                                      = 1.6               

For machine M2:

Clocks per instruction (CPI) = (60/100)*2 + (30/100)*3 + (10/100)*4

                                                      = 1.2 + 0.9 + 0.4

                                                     = 2.5

b ) Calculate the average MIPS ratings for each machine , M1 and M2.

Answer:

Given that clock rate for machine1 = 80 MHz = 80*10⁶

clock rate for machine2 = 100 MHz = 100*10⁶

CPI for machine1 = 1.6

CPI for machine2 = 2.5

For machine M1:

                Average MIPS rating = Clock Rate / (CPI*10⁶)

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

                                                       = 50

For machine M2:

                Average MIPS rating = Clock Rate / (CPI*10⁶)

         = (100*10⁶) / (2.5*10⁶)

         = 40