Question

6.5 The time taken by machines A, B, and C to execute a given task is

A 16m, 9s

B 14m, 12s

C 12m, 47s

What is the performance of each of these machines relative to machine A?

6.6 Why is clock rate a poor metric of computer performance? What are the relative strengths and weaknesses of clock speed as a performance metric?

6.7 What are the relative strengths and weaknesses of the MIPS as a metric of computer performance?

Answer 1

6.5

For finding the performance of a machine relative to another machines, divide the execution time of the machine to the execution time of another machine.

It is given that execution time of machine A is 16m, 9s = 969 s

Execution time of machine B is 14m, 12s = 852 s

Execution time of machine C is 12m, 47s = 767 s

Performance of machine B relative to machine A

= Execution time of A/Execution time of B

= 969/852

= 1.13

Performance of machine C relative to machine A

= Execution time of A/Execution time of C

= 969/767

= 1.26

6.6

The speed at which the internal tasks and operations are performed within the computer is the clock rate. There are computers often without clocks and some have various clocks for different parts like CPU, the Bus and the memory.

Weakness

The clock rate is not a good metric for computer because the clock rate does not give insights about the amount of work being done.

The performance depends on different factors like the cache memory and the instruction set.

Strength

The clock rate may however be suitable for comparing two identical processes whose software environments are similar.

6.7

Strength of MIPS as a metric of computer performance

MIPS (Million instructions per second) is a better metric in comparison to clock cycle rate. It provides more information indicating the number of instructions per second.

Weakness

The system hardware and software are not considered and the amount of work which is done by the instructions are not taken into account.