libownsteal

A blazing-fast, single-file lock-free Chase-Lev Task-Stealing Deque implemented in standard C++20/C++23 Modules.

Designed for ultra-low latency scheduling systems, parallel game engines, and high-performance concurrent runtimes.

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Key Features

• Lock-Free Architecture: Single-writer, multi-reader queues utilizing explicit atomic memory barriers (std::memory_order_release / acquire).
• Hardware Cache Isolation: Key indices are explicitly separated with alignas(64) to completely prevent CPU cache false sharing.
• Modern C++ Modules: Full native support for standard module interfaces via export module TaskStealingDeque;.
• Zero Runtimes Allocations: Built around a static ring-buffer pattern with fixed capacities to guarantee deterministic execution time.

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Quick Start

Because libownsteal is built entirely using standard C++ modules, you can drop the .cppm file directly into your workspace and import it:

import TaskStealingDeque;
#include <iostream>
#include <utility> 

struct MyTask {
    int id;
    // Define a default constructor so the receiver objects can be initialized
    MyTask() : id(0) {} 
    MyTask(int identifier) : id(identifier) {}
    
    void execute() const { std::cout << "Running task " << id << "\n"; }
};

int main() {
    // Capacity must be a power of two
    TaskStealingDeque<MyTask, 1024> queue;
    
    // 1. Push from the owner thread (explicitly moving the temporary object)
    bool pushed = queue.push(MyTask(42));
    if (pushed) {
        std::cout << "Task pushed successfully!\n";
    }
    
    // 2. Pop from the owner thread
    MyTask localTask;
    if (queue.pop(localTask)) {
        localTask.execute();
    }
    
    // 3. Concurrent thief threads can safely steal j*bs
    MyTask stolenTask;
    if (queue.steal(stolenTask)) {
        stolenTask.execute();
    }
    
    return 0;
}

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Performance Context

• Memory Layout: Keeps memory footprints perfectly contiguous in cache.
• Algorithmic Bounds: Push and Pop operations execute in $O(1)$ constant time with minimal atomic contention.

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License

This project is open-source software licensed under the GNU General Public License v3 (GPL-3.0). See the LICENSE file for details.

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copyright mxreal64, 2026