CPU Scheduler Simulator

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

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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

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Quick Start

🐧 Linux / macOS

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

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

2. Install Emscripten:

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

3. 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/

4. Run:

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

🪟 Windows (PowerShell)

1. Prerequisites:

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

2. Install Emscripten:

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

3. 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\

4. 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

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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

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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

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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/)

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License

MIT License — see LICENSE

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Author

Mohammad Hamd Ashfaque
GitHub: @Premity

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Version: 1.0.0 | Last Updated: December 2025