3.3 Suppose a computer has an atomic swap instruction, defined as follows: Swap (varl, var2): (tmp = varl; varl = var2; var2 = tmp; ) In the above, tmp is an internal register. (a) Using Swap, develop a solution to the critical section problem for n pro- cesses. Do not worry about the eventual entry property. Describe clearly how your solution works and why it is correct. (b) Modify your answer to (a) so that it will perform well on a multiprocessor system with caches. Explain what changes you make (if any) and why. (c) Using Swap, develop a fair solution to the critical section problem-namely, one that also ensures eventual entry to each waiting process. The key is to order the processes, where first-come, first-served is the most obvious ordering. Note that you cannot just use your answer to (a) to implement the atomic action in the ticket algorithm, because you cannot get a fair solution using unfair components. You may assume that each process has a unique identity, say, the integers from 1 to n. Explain your solution, and give convincing arguments why it is correct and fair.

3.3 Suppose a computer has an atomic swap instruction, defined as follows: Swap (varl, var2): (tmp = varl; varl = var2; var2 = tmp; ) In the above, tmp is an internal register. (a) Using Swap, develop a solution to the critical section problem for n pro- cesses. Do not worry about the eventual entry property. Describe clearly how your solution works and why it is correct. (b) Modify your answer to (a) so that it will perform well on a multiprocessor system with caches. Explain what changes you make (if any) and why. (c) Using Swap, develop a fair solution to the critical section problem-namely, one that also ensures eventual entry to each waiting process. The key is to order the processes, where first-come, first-served is the most obvious ordering. Note that you cannot just use your answer to (a) to implement the atomic action in the ticket algorithm, because you cannot get a fair solution using unfair components. You may assume that each process has a unique identity, say, the integers from 1 to n. Explain your solution, and give convincing arguments why it is correct and fair.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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