Homework P&H Ch. 1

Answer the following questions about Patterson and Hennessy, Chapter 1. You only need to turn in those that have a point count assigned.

  1. (1 point) What are the five classical components of a computer? What does each one do?
  2. (1 point) Which of the following have exhibited exponential improvement over the past few decades?
    1. transistor density
    2. memory capacity
    3. memory access time
    4. disk storage capacity
    5. disk access time
  3. Why has processor clock speed not increased in the past few years? What have processor manufacturers done to compensate for this?

  4. (1 point) Improvements in a processor lead to a reduction in execution time for a program from 7 seconds to 5 seconds. What is the percentage improvement for performance?
  5. What are the two current SPEC benchmark suites for processor performance?
  6. Which of the factors in the performance equation are most likely to be affected by the following changes to a processor?
    1. Adding more powerful instructions
    2. Improvements in transistor technology
    3. Large scale reorganizations, such as pipelining
  7. (1 point) In a certain processor, 20% of the executed instructions are branches and jumps, 20% are loads and stores, and 60% are arithmetic and logical instructions. Branches and jumps execute in 3 cycles, loads and stores execute in 5 cycles, and arithmetic and logical operations execute in 4 cycles. What is the effective CPI?
  8. If you were a computer architect, how would you obtain the percentages in the previous problem? How would you obtain the cycle counts for the different types of instructions?
  9. (1 point) An incremental modification of the above processor reduces the cycle count for arithmetic and logical instructions from 4 cycles to 3 cycles. This modification increases the cycle time by 10%. No new instructions are added so the instruction count is unchanged. What is the overall percentage improvement in performance?
  10. (1 point) The current version of a processor spends 45% of its time on arithmetic and logic instructions, 30% on loads and stores, and 25% on branches. Modifications to the circuitry improve performance on loads and stores by 50% and performance on branches by 25%. The performance on arithmetic and logic instructions is unchanged. What is the overall performance improvement, expressed as a percentage?