A program consists of 4 types of instructions as shown below

A program consists of 4 types of instructions as shown below. What is the average CPI? How long does a program take to run on a processor with a 2GHz clock if it has 10^10 instructions and a CPI of 2? A program takes 15 seconds to execute. There are 10^10 instructions with a CPI of 1.5. What is the clock cycle time?

Solution

1) To calculate average CPI the formula is

CPI = (ICi)(CCi)/IC

ICi - no of instruction for given instruction type i

CCi - the clock-cycles for that instruction type

Summation of multiplication of ICi and CCi

CPI = (15*1+25*2+40*3+20*4)/(15+25+40+20)

CPI = (15+50+120+80)/(100)

CPI= 265/100

CPI = 2.65