CPU Scheduler Simulator

An interactive CPU scheduling simulator with a WebAssembly-powered web interface.

Features

Six Scheduling Algorithms: FCFS, SJF, SRTF, Round Robin, Priority (Preemptive & Non-Preemptive)
Aging Mechanism: Configurable priority boost to prevent starvation
Interactive Web UI
- Real-time Gantt Chart
- Live Ready Queue visualization
- Process Statistics with color-coded states
- Light/Dark Mode Toggle
- Table-based process input
Metrics: Waiting Time, Turnaround Time, Response Time

Quick Start

🐧 Linux / macOS

Dependencies: Install git, python3, cmake, and g++.

# Ubuntu/Debian
sudo apt update
sudo apt install git python3 cmake g++

Install Emscripten:

git clone https://github.com/emscripten-core/emsdk.git && cd emsdk
./emsdk install latest && ./emsdk activate latest
source ./emsdk_env.sh
cd ..

Build:

git clone https://github.com/Premity/process-scheduling.git
cd process-scheduling
mkdir build && cd build
emcmake cmake .. && emmake make
cp scheduler_wasm.js scheduler_wasm.wasm ../www/

Run:

cd ..
g++ -std=c++17 src/server_main.cpp -o scheduler_server -I include -lpthread
./scheduler_server

🪟 Windows (PowerShell)

Prerequisites:
- Install Git
- Install Python 3
- Install MinGW-w64 (ensure g++ and mingw32-make are in PATH)
- Install CMake
Install Emscripten:

git clone https://github.com/emscripten-core/emsdk.git
cd emsdk
./emsdk install latest
./emsdk activate latest
./emsdk_env.bat
cd ..

Build:

git clone https://github.com/Premity/process-scheduling.git
cd process-scheduling
mkdir build; cd build
emcmake cmake -G "MinGW Makefiles" ..
emmake mingw32-make
Copy scheduler_wasm.js ..\www\
Copy scheduler_wasm.wasm ..\www\

Run:

cd ..
# Compile server (linking ws2_32 for Windows sockets)
g++ -std=c++17 src/server_main.cpp -o scheduler_server.exe -I include -lws2_32 -static
scheduler_server.exe

Project Structure

.
├── cmake/                # CMake configuration
├── include/
│   ├── scheduler.h       # Core scheduler API
│   ├── httplib.h         # cpp-httplib (header-only)
│   └── json.hpp          # nlohmann/json (header-only)
├── src/
│   ├── scheduler.cpp     # Scheduler implementation
│   ├── wasm_main.cpp     # WebAssembly bindings
│   └── server_main.cpp   # Native C++ static file server
├── www/                  # Web UI (HTML, CSS, JS)
├── CMakeLists.txt
├── LICENSE
└── README.md

Scheduling Algorithms

Algorithm	Type	Selection Criteria
FCFS	Non-Preemptive	Earliest arrival
SJF	Non-Preemptive	Shortest burst time
SRTF	Preemptive	Shortest remaining time
Round Robin	Preemptive	Time quantum rotation
Priority	Preemptive	Lowest priority value
PriorityNP	Non-Preemptive	Lowest priority value

Aging Mechanism

Prevents starvation by boosting priority of waiting processes:

scheduler.setAging(true);
scheduler.setAgingThreshold(5);    // Boost every 5 ticks
scheduler.setAgingBoostAmount(1);  // Decrease priority by 1

Dependencies

C++17 Compiler (GCC/Clang/MSVC)
CMake 3.10+
Emscripten SDK (for WebAssembly build)
nlohmann/json (included in include/)
cpp-httplib (included in include/)

License

MIT License — see LICENSE

Author

Mohammad Hamd Ashfaque
GitHub: @Premity

Version: 1.0.0 | Last Updated: December 2025

Premity/process-scheduling