Question Bank: Parallel computing Faculty: Ayaz Ahmed Shariff K

Modules covered: Processor organizations, Mapping and Scheduling

1. What are three important models of parallel computing? Explain each one of them?

2. Explain the need of networks in parallel processing. Discuss about the following networks.

(a) Hyper tree networks (b) Hypercube Networks

(c) Mesh networks (d) Pyramid networks

(e) Butterfly networks (f) Shuffle exchange networks

3. Explain shuffle exchange network with 8 nodes?

4. Discuss about 24 cube connected cycle network?

5. Define the terms diameter, Bisection width, Number of edges per node, Max edge length,

speedup, parallelizability, efficiency?

6. Define the terms task graph, gantt chart, optimal schedule, simple task graphs, chain,

necklace, perfect shuffle, multistage network, Omega network, Dilation?

7. What is the difference between a binary k-cube and a cube-connected network of degree k?

8. Given a shuffle-exchange network, prove that if a shuffle link connects nodes i and j, then j is

a single-bit left cyclic rotation of i? Prove that the number of necklaces in an n-node shuffle

exchange network is O(2k / k)??

9. Show how to perform the perfect shuffle network’s exchange operation on a de-bruijn

network?

10. Is it possible for the average speedup exhibited by a parallel algorithm to be superlinear?

11. Embed a complete binary tree with 31 nodes in a 2D mesh, or prove no such embedding

exists?

12. With a block diagram, explain processor arrays?

13. Explain types of Multiprocessors with examples?

14. Write a block diagram of the sequent symmetry UMA multiprocessor?

15. How cache consistency is maintained in UMA Multiprocessors?

16. How processors communicate in multicomputers? Briefly discuss some popular

multicomputers?

17. Discuss the Flynn’s taxonomy for classifying for serial and parallel computer architectures

with simple block diagrams?

18. How to embed a complete binary tree of height 3 into a 2 D Mesh? Is it possible to embed a

tree greater than height 4 in a 2 D Mesh without increasing the dilation beyond 1?

19. Illustrate with example, embedding of binomial tree into 2 D mesh?

20. Discuss embedding of different graphs into hypercube processor organization with some

examples?

21. Prove that a dilation-1 embedding of complete binary tree of height n into hypercube of

dimension n+1 does not exist if n>1?

22. Prove that a binomial tree of height n can be embedded in a hypercube of dimension n such

that dilation is 1?

23. What are properties of encoding to embed rings and meshes into hypercube?

24. What is gray code? Does gray code provide solution to embed a mesh onto hypercube?

Explain the mapping of 4 X 8 mesh into a 32-node hypercube?

25. Explain mapping of an 8 node ring into an 8-processor hypercube?

26. What are different dynamic load balancing algorithms on multicomputers?

27. What are deterministic models and non-deterministic models?

28. Illustrate Coffman-Graham scheduling algorithm with an example? Does Coffman graham

scheduling algorithm produce an optimal schedule?

29. What is task graph? Explain the importance of embedding one graph into another?