Problem 2: Duplicated Processors ( do 3 of 6 for 18 pts)

The following questions are about Meep and Moop, two experimental machines that Muffin,the stuffed owl, is benchmarking when she's not guarding her mistress, the lovely Jalenstrix. Some of the questions use the information in the table below; so, read carefully before assuming that Muffin left out some crucial pellet of information.

Do exactly three (3) of the six (6) problems below. Be sure to write down the number of the problem that you are doing in your exam booklet.

	Meep	Moop
Floating Point IC	$2 \times 10^{6}$	$3 \times 10^{6}$
Integer IC	$198 \times 10^{6}$	$2 \times 10^{6}$
Average CPI	2	2
Clock Cycle Time	$2 \times 10^{-9}$	$2 \times 10^{-12}$

2.1

Answer these three questions about the MEEP machine.

2.1.a

Write an expression for the performance of MEEP.

2.1.b

Write an expression for the MIPs rating of MEEP.

2.1.c

Is the MIPS rating a reliable predictor of performance for a given machine? Explain your answer for full credit.

2.2

Suppose that you modify the MOOP so that the average CPI increases by 25% and the IC decreases by 30%. How much faster must the new clock chip be to increase the CPU performance rate? Explain your answer clearly for full credit.

2.3

Suppose that we give MEEP a new optimizing compiler. On the average, should we expect the IC to decrease? Explain your answer for full credit.

2.4

Suppose ALU instructions on MOOP take 2 clock cycles (cc), jumps take 1 cc, and all other instructions take 3 cc's. Answer the following questions

2.4.a

If 40% of the instructions are ALU instructions and 10% are jumps, what is the average CPI?

2.4.b

Suppose that the MOOP optimizing compiler decreases ALU instructions to 20% and drops the number of jumps to 7%, without modifying the frequencies of any other instructions What change, if any, would you expect in the execution time of a program on MOOP? Justify your answer for full credit.

2.5

An enhancement of MEEP gives a speedup of 10 whenever it can be used in a program. Suppose that the ehancement is used half of the time when the enhanced mode is in use. Answer these two questions regarding MEEP performance under this enhancement.

2.5.a

What is the overall speedup from this enhancement?

2.5.b

What percent of the original MEEP code was enhanced?

2.6

Suppose that we modify the MOOP ISA to decrease the CPI. Should we expect to see a decrease in the average execution time? Why or why not?

THE REMAINDER OF THE TEST DEALS WITH THE FOLLOWING MIPS ARCHITECTURE. SO DON'T SKIP THIS SECTION.

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