Configurable CPU Scheduling Simulator

A configurable CPU scheduling simulator written in C that implements and analyzes multiple operating system scheduling policies. The project focuses on correctness, fairness, starvation detection, and empirical performance comparison rather than only algorithm implementation.

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Features

• Implements multiple CPU scheduling algorithms:
  • First Come First Serve (FCFS)
  • Shortest Job First (SJF)
  • Shortest Remaining Time First (SRTF – preemptive)
  • Priority Scheduling
  • Round Robin (configurable time quantum)
• Gantt chart visualization with proper handling of idle CPU time
• Computes key scheduling metrics:
  • Average Waiting Time (WT)
  • Average Turnaround Time (TAT)
  • Fairness (standard deviation of waiting times)
  • Starvation detection
• Stress-testing mode to empirically compare scheduling policies on randomized workloads
• Modular design with Makefile-based build system

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Technologies Used

• Language: C
• Platform: Unix/Linux
• Build System: Makefile

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Project Structure

• main.c – Command-line interface and control logic
• scheduler.h – Scheduler function declarations
• scheduler_fcfs.c – FCFS scheduling implementation
• scheduler_sjf.c – Non-preemptive SJF scheduling
• scheduler_sjf_preemptive.c – Preemptive SJF (SRTF)
• scheduler_priority.c – Priority scheduling
• scheduler_rr.c – Round Robin scheduling
• metrics.c – Waiting time, turnaround time, fairness, starvation metrics
• metrics.h
• gantt.c – Gantt chart visualization
• gantt.h
• process.h – Process data structure
• config.c – Global configuration (e.g., Gantt toggle)
• config.h
• processes.txt – Input process list
• Makefile – Build configuration
• scheduler – Compiled executable

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Build Instructions

make clean make

This generates the executable scheduler.

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Run Instructions

Run individual scheduling policies

./scheduler fcfs ./scheduler sjf ./scheduler priority ./scheduler rr 2

Run all policies with summary output

./scheduler all

Run stress testing and policy analysis

./scheduler --stress 1000