mengrao/spsc_queue

A highly optimized single producer single consumer message queue C++ template

spsc_queue's Issues

我的测试结果是SPSCQueueOPT性能远不如SPSCQueue

Target Architecture (armv8 compatibility)?

Hi,

I am trying to figure out the portability / correctness of SPSCQueue.h on different architetures, especially armv8.

For this, I am mostly going by https://www.kernel.org/doc/Documentation/memory-barriers.txt
My understanding is that both pop / push obviously need to happen in correct order / atomic.

I am familiar with
__asm__ volatile("" ::: "memory")
to enforce a compiler level barrier and
__asm__ volatile ("mfence" ::: "memory")
to actually enforce a cpu barrier at runtime.

This should boil down to _mm_mfence (x86) or __mf (arm).

It's not clear to me how, e.g.
asm volatile("" : "=m"(data) : "m"(read_idx) :); // memory fence
enforce a barrier at runtime.

Is this the case because x86 has a more or less strict memory ordering, and the ops are atomic (are they?)? Or is a full memory fence simply not needed in this case.

Also: How portable is this to architectures with weak memory ordering, e.g. to armv8?
Would std::atomic_thread_fence be needed as replacement? I see you used that at the beginning before replacing it with the asm instructions.

Many thanks for your efforts! :-)

multhread_q 我跑了下要500ns，可能原因是？

机器配置：Gold 6144 3500MHZ，同一个node上面隔离出来2个CPU 绑核做的测试。
请问你的机器配置是啥能跑到50-100ns？或者需要做些其他的配置？

消费者感知消息问题

你好， 我测试了SPSCQueue.h的代码，发现前CNT条消息，收不到？要写满CNT条消息后，消费者才能读取到第1条消息