Exercise 1.6 Compilers can have a profound impact on the performance of an application on a given processor. This problem will explore the impact compilers have on execution time.

Compiler A Compiler B # Instructions Execution time # Instructions Execution time

a. 1.00E+09 1 s 1.20E+09 1.4 s

b. 1.00E+09 0.8 s 1.20E+09 0.7 s 1.6.1 [5] <1.4> For the same program, two different compilers are used. The table above shows the execution time of the two different compiled programs. Find the average CPI for each program given that the processor has a clock cycle time of 1 nS.
1.6.2 [5] <1.4> Assume the average CPIs found in 1.6.1, but that the compiled programs run on two difference processors. If the execution times on the two processors are the same, how much faster is the clock of the processor running compiler A’s code versus the clock of the processor running compiler B’s code?
1.6.3 [5] <1.4> A new compiler is developed that uses only 600 million instructions and has an average CPI of 1.1. What is the speed-up of using this new compiler versus using Compiler A or B on the original processor of 1.6.1?
Consider two different implementations, P1 and P2, of the same instruction set.
There are fi ve classes of instructions (A, B, C, D, and E) in the instruction set. P1 has a clock rate of 4 GHz, and P2 has a clock rate of 6 GHz. The average number of cycles for each instruction class for P1 and P2 are listed in the following table.
Class CPI on P1 CPI on P2

a. A 1 2 B 2 2 C 3 2 D 4 4 E 5 4 Class CPI on P1 CPI on P2

b. A 1 2 B 1 2 C 1 2 D 4 4 E 5 4 1.6.4 [5] <1.4> Assume that peak performance is defi ned as the fastest rate that a computer can execute any instruction sequence. What are the peak performances of P1 and P2 expressed in instructions per second?
1.6.5 [5] <1.4> If the number of instructions executed in a certain program is divided equally among the classes of instructions in Problem 2.36.4 except for class A, which occurs twice as often as each of the others, how much faster is P2 than P1?
1.6.6 [5] <1.4> At what frequency does P2 have the same performance as P1 for the instruction mix given in 1.6.5?