1
EE 357 Homework 5
Fall 2009
Nazarian
Name: ___________________________________________
Assigned Tuesday, Nov. 17
Due:
Monday, Nov. 30 (EEB340 at 5pm)
Score: ________
1)
Performance and Amdahl’s Law
a)
Exercises 1.3.1-1.3.3 in CO&D, 4
th
Ed. page 59:
Consider three different processors P1, P2, and P3 executing the same instruction set with
the clock rates and CPIs given in the following table:
Processor
Clock Rate
CPI
Processor
P1
2 GHz
1.5
P1
P2
1.5GHz
1.0
P2
P3
3 GHz
2.5
P3
1.3.1 Which processor has the highest performance?
1.3.2 If the processors each execute a program in 10 seconds, find the number of cycles and
the number of instructions.
1.3.3 We are trying to reduce the time by 30% but this leads to an increase of 20% in the
CPI. What clock rate should we have to get this time reduction?
b)
Exercises 1.5 (1.5.1-1.5.6) in CO&D, 4
th
Ed. page 60-61.
For problems 1.5.2-1.5.3
when it says that class A (or E) occurs twice as often as each of the others, let us
assume that means that for every 6 instructions, on average two would be class A (or
E) and one instruction from every other class:
Consider two different implementations, P1 and P2, of the same instruction set. There are
5 classes of instructions, A, B, C, D, and E, in the instruction set. The clock rate and CPI
of each class is given below.
Clock Rate
CPI Class A
CPI Class B
CPI Class C
CPI Class D
CPI Class E
a.
P1
1.0GHz
1
2
3
4
3
P2
1.5GHz
2
2
2
4
4
b.
P1
1.GHz
1
1
2
3
2
P2
1.5GHz
1
2
3
4
3

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