dodng / fast_ring_queue

A fast no_lock RingQueue between 2 threads (25M WrtieRead per second)

1. What is a ring queue

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• the data is "first in first out".
• prev data of queue head is the queue tail.
• the data of ring can reuse.

2. The advantages of ring queue

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• Guaranteed elements are first-in, first-out

• Element space can be reused

• Provides an efficient mechanism for multithread data transfer.

3. Ring queue of work example

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• Linux between kernel and system to transfor network data( PACKET_RX_RING and PACKET_TX_RING )

4. Actual test results

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• In CentOS 5.5 (cpu per core frequency 1200MHz) .
• ring queue length is 10000, one element data size is 4 bytes
• [ring_test] the element writted and then to read is about 25 million per second.
• [notify_ring_test] the element writted and then to read is about 20 million per second.

fast_ring_queue's Issues

This is a C++ project not C

This project is listed as a C based source and its C++

一点困惑

 无锁队列本质上还是有锁，只不过锁的粒度很小，通常是一个标志。

一般通过CAS（compare&set）和TAS（test&set）等原子操作结合忙等待实现的
if (tag_p->tag_value == CAN_WRITE)
{ user_data = (u_char *)g_p + sizeof(TAG);
tag_p->tag_value = WRITING; }
`
我看你的实现代码里面，判断和写标志并不是原子的操作？是否还是会有多线程的问题？有点疑惑，
期待您解答下。

两个线程同时写 怎么实现 无锁环形队列