SPSCQueue单一消费者等待和无锁定大小队列

SPSCQueue 是用 C++ 11 编写的单个生产者单一消费者等待和无锁定大小队列。

示例代码

SPSCQueue q(2);
auto t = std::thread([&] {
  while (!q.front());
  std::cout << *q.front() << std::endl;
  q.pop();
});
q.push(1);
t.join();

使用

• SPSCQueue(size_t capacity);

  Create a SPSCqueue holding items of type T with capacity capacity. Capacity need to be greater than 2.

• void emplace(Args &&... args);

  Enqueue an item using inplace construction. Blocks if queue is full.

• bool try_emplace(Args &&... args);

  Try to enqueue an item using inplace construction. Returns true on success and false if queue is full.

• void push(const T &v);

  Enqueue an item using copy construction. Blocks if queue is full.

• template void push(P &&v);

  Enqueue an item using move construction. Participates in overload resolution only if std::is_constructible::value == true. Blocks if queue is full.

• bool try_push(const T &v);

  Try to enqueue an item using copy construction. Returns true on success and false if queue is full.

• template void try_push(P &&v);

  Try to enqueue an item using move construction. Returns true on success and false if queue is full. Participates in overload resolution only if std::is_constructible::value == true.

• T *front();

  Return pointer to front of queue. Returns nullptr if queue is empty.

• pop();

  Dequeue first elment of queue. Invalid to call if queue is empty. Requires std::is_nothrow_destructible::value == true.

一旦一个单一的写线程可以执行入队列的操作时，只有一个单一的读线程可以执行取队列操作，其他的使用都是不允许的。

实现原理

底层实现是一个环形缓冲区。

参考资料:

• Intel. Avoiding and Identifying False Sharing Among Threads.
• Wikipedia. Ring buffer.
• Wikipedia. False sharing.

性能测试

以下测试结果是基于 2 socket machine with 2 x Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz.