Consider three different processors P1 P2 and P3 executing t

Consider three different processors P1, P2 and P3 executing the .same instruction set. P1 fans n 3 GHz clock rate and a CPI of 1.5. P2 1ms n 2.8 GHz clock rate and a CPI of 1.0. P3 has a 4.0 GHz clock rate and has a CPI of 2.0. What is the instructions per second for these three processors? If the processors each execute a program in 100 seconds, find the mm, her of cycles and the number of instructions. We are trying to reduce the execution time by 40% but this lead to an increase of 30% in the CPI. What dock rate should we have to get this time reduction?

Solution

No.of cycles = time × clock rate cycles(P1) = 100 * 3* 1,000,000,000 = 300,000,000,000

(P2) = 100 * 2.8 * 1,000,000,000 = 280,000,000,000

(P2) = 100 * 4 * 1,000,000,000 = 400,000,000,000

No. of instructions = No. cycles/CPI (P1) = 300,000,000,000 / 3* 1,000,000,000 = 100

No. of instructions(P2) = 280,000,000,000 /  2.8 * 1,000,000,000 = 100

No. of instructions(P3) = 400,000,000,000 / 4 * 1,000,000,000 = 100