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
SPSCQueueq(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
SPSCqueueholding items of typeTwith capacitycapacity. 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
trueon success andfalseif queue is full. -
void push(const T &v);Enqueue an item using copy construction. Blocks if queue is full.
-
templatevoid push(P &&v); Enqueue an item using move construction. Participates in overload resolution only if
std::is_constructible. Blocks if queue is full. -
bool try_push(const T &v);Try to enqueue an item using copy construction. Returns
trueon success andfalseif queue is full. -
templatevoid try_push(P &&v); Try to enqueue an item using move construction. Returns
trueon success andfalseif queue is full. Participates in overload resolution only ifstd::is_constructible. -
T *front();Return pointer to front of queue. Returns
nullptrif 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.
| NUMA Node / Core / Hyper-Thread | Throughput (ops/ms) | Latency RTT (ns) |
|---|---|---|
| #0,#0,#0 & #0,#0,#1 | 63942 | 60 |
| #0,#0,#0 & #0,#1,#0 | 37739 | 238 |
| #0,#0,#0 & #1,#0,#0 |
