基于硬件 CAS 原语的高效多字无锁同步算法

摘要

Lock-based synchronization may become a performance bottleneck which limits the concurrency in shared -mem-ory machines .In order to solve this problem ,a lock-free synchronization algorithm based on hardware CAS (Compare And Swap ) primitive is proposed in this paper .In the proposed method ,compare and swap instruction provided by underlying processor is used to implement non-blocking synchronization for shared variables in multi-core or multi-thread environment .Global mark value is in-troduced to avoid performance overhead caused by bits reservation of memory word in the traditional design ,and guarantee the con-sistency .Theoretical analysis and experimental results show that the proposed method can efficiently support arbitary multi-word CAS synchronization ,improve the concurrent access performance and provide good scalability .%共享内存体系结构下，为解决锁同步导致的并发性能瓶颈，本文提出了一种基于硬件CAS （比较交换）原语的无锁同步算法。该算法利用底层处理器提供的比较交换指令，实现了在多核多线程环境下对共享变量的非阻塞同步操作，通过采用全局标记值的方式，避免了传统设计中由于使用内存字标记导致的性能开销，同时确保数据在并发访问中的一致性。实验结果表明，本文算法可以高效地支持任意多字的CAS同步，提高了对共享数据的并发访问性能，具有较好的可扩展性。