Computer Architecture Assignment and Solution

Computer Architecture and Assembly Language Programming

(EE - 204), Fall 2015

Assignment # 1

Instructor: Faraz Idris Khan Total points = 20

Amadhl's Law Speedup Calculation (10)

1)The following table shows the execution time of five routines of a program running on different numbers of processors.

a)Find the total execution time, and how much it is reduced if the time of routines A, C, & E is improved by 15%.

b) By how much is the total time reduced if routine B is improved by 10%?

c) By how much is the total time reduced if routine D is improved by 10%?

2) Execution time in a multiprocessor system can be split into computing time for the routines plus routing time spent sending data from one processor to another. Consider the execution time and routing time given in the following table.

For each doubling of the number of processors, determine the ratio of new to old computing time and the ratio of new to old routing time.

Processor Performance (10)

The table below describes the performance of two processors, the rAlpha and the c86, and two compilers on a common 'benchmark' program

a. Which is the best compiler-machine combination?

b. Both hardware vendors release quad-core versions of the processor for 1.7x the cost of the single core version. The results on the two new systems:

Assume the benchmarks used are perfectly parallelizable i.e. the cores process equal parts of the program independently and at the same time. Now which combination performs best?

c. Using the metric (Cycles/s)*Cores/(Dollars^2), which is the best machine? Is this metric useful?