Lottery Scheduler for xv6

Overview

This project implements a Lottery Scheduler for the xv6 operating system. The scheduler is a probabilistic CPU scheduling algorithm where each process is assigned a certain number of tickets. A random lottery determines which process runs next, with the probability of selection based on the number of tickets a process holds. This project replaces the default Round Robin scheduler in xv6.

Objectives

• Gain deeper understanding of the xv6 kernel.
• Implement a lottery scheduler by modifying the scheduler code in proc.c.
• Add system calls to set the number of tickets and retrieve process statistics.
• Generate a graph illustrating the proportional CPU allocation among processes.

Features

1. Lottery Scheduling: Processes receive a portion of the CPU in proportion to the number of tickets assigned.
2. Ticket Assignment System Call: int settickets(int num) sets the number of tickets for the calling process.
3. Process Statistics System Call: int getpinfo(struct pstat *p) retrieves statistics on process execution.

Testing

1. Multiple Test case files added to the users directory to test the lottery scheduler

Graph Generation

1. Run the scheduler with three processes having tickets in a 3:2:1 ratio.
2. Record the results of time slices received by each process.
3. Plot a graph illustrating CPU allocation over time to verify the proportionality of the lottery scheduler.