I am a student from the Hong Kong Metropolitan University (HKMU).
This "CPU Scheduling Algorithms Simulator" is created for the course of "Data Structure, Algorithms, and Problem Solving" (8090SEF).
It help me study my another course, Operating System (OS) (8670SEF).
In early 2026, the OS course teaches something about different type of CPU scheduling. As a human, we need to be very careful each step and draw perfect gantt charts so that we could get a meaningful comparsion of the differences of different type of scheduling algorithms.
In order to save time and do every step well, I prepared this graphical simulator for visualizing and comparing CPU scheduling algorithms.
This tool allows users to input processes, run multiple scheduling algorithms simultaneously, and view detailed results including Gantt charts, per-time-unit timelines, and performance metrics.
3.1. Interactive GUI built with Tkinter
3.2. Six Scheduling Algorithms:
(i) FCFS (First-Come, First-Served) - Non-preemptive
(ii) SJF (NP) (Shortest Job First) - Non-preemptive
(iii) SRTF (Shortest Remaining Time First) - Preemptive
(iv) Round Robin - Preemptive with configurable time quantum
(v) Priority (NP) - Non-preemptive priority-based
(vi) Priority (Preemptive) - Preemptive priority-based
3.3. Key Functionality
(i) Interactive Process Management - Add, edit, delete, and randomize processes
(ii) CSV Import/Export - Load and save process lists
(iii) Sample Data - One-click load of pre-configured test processes
(iv) Real-time Visualization - Gantt charts with color-coded process execution
(v) Performance Metrics - Waiting time, turnaround time, response time, CPU utilization, throughput
(vi) Algorithm Comparison - Side-by-side bar charts comparing all algorithms
(vii) Execution Logging - Detailed timeline of arrivals, preemptions, and completions
(viii) Export Reports - Excel workbooks and PDF documents with complete results
4.1 Python 3.10 or later
4.2 matplotlib
4.3 openpyxl
5.1 Download the source codes.
5.2 Install dependencies with:
pip install -r requirements.txt
5.3 Run the script via Python
python main.py
6.1. Add Processes
Fill in the form in the left panel:
• Arrival Time - When the process arrives (≥ 0)
• Burst Time - CPU time needed (positive integer)
• Priority - Lower number = higher priority
Click "Add / Update" or press Enter.
6.2. Quick Setup Options
• Load Sample Set - Loads 5 pre-configured test processes
• Random - Generates a random process
• Import CSV - Load from CSV file
6.3. Select Algorithm & Run
• Choose an algorithm from the dropdown
• For Round Robin, set the time quantum (default: 2)
• Click "Run Simulation"
6.4. Explore Results
• Dashboard - Gantt chart and metrics for selected algorithm
• Comparison - Compare all six algorithms
• Execution Log - Timeline view
• Result Table - Per-process statistics
6.5. Export Reports
• Export to Excel - Complete workbook with all results and charts
• Export to PDF - Multi-page PDF report
7.1. Understanding the Metrics
Metric Description Ideal
Waiting Time Time spent in ready queue Lower
Response Time Time until first CPU allocation Lower
Turnaround Time Total time from arrival to completion Lower
CPU Utilization Percentage of time CPU is busy Higher
Throughput Processes completed per time unit Higher
7.2. Algorithm Selection Guide
Use Case Recommended Algorithm
Batch systems, simple implementation FCFS
Minimizing average waiting time SJF / SRTF
Interactive/Time-sharing systems Round Robin
Real-time/Urgent tasks Priority (Preemptive)
Mixed workload analysis Compare all using Comparison tab
8.1 Gantt Chart: Horizontal bars show which process occupies the CPU over time.
8.2 Timeline Breakdown: Detailed per-time-unit events including arrivals, queue state, remaining times.
8.3 Results Table: For each process:
(i) Start time
(ii) completion time
(iii) Turnaround time = completion - arrival
(iv) Waiting time = turnaround - burst
(v) Response time = first start - arrival
(vi) Averages: Average turnaround, waiting, and response times for the algorithm.
9.1 All times can be floating-point numbers.
9.2 Process IDs are assigned sequentially starting from 1.
9.3 The simulator assumes time is discrete in 1-unit steps for timeline granularity.
10.1 This project is open-source and available under the MIT License. Feel free to modify and distribute.
11.1 Main Layout
11.2 Export to Excel
11.3 Export to PDF
