通过对多核同步过程中的访存行为进行分析,提出了一种识别同步类型的方法,并设计了一种实现同步优化的新的cache一致性协议。该协议增加了一个用于记录同步信息的cache状态,通过阻塞的方式可以让多个处理器核串行地完成同步操作,保证同步操作中原子指令能够顺利执行成功,从而大大减少由多核同步冲突引发的访存请求数量,将多核同步过程中的访存行为优化到了几乎最好的情况。实验结果表明,通过同步优化,这个新的cache一致性协议能够使多核同步的性能提升到接近最理想的结果。实验表明,相比传统的cache一致性协议,实验中采用的几个标准多核性能测试程序优化后的同步性能提升了1倍,而并行程序整体运行时间降低25%。
Based on the memory accessing analysis for the synchronization process of chip multiprocessors ( CMPs), a method to recognize the type of synchronization was proposed, and a novel cache coherence protocol for optimization of the synchronization of CMPs was designed. The protocol adds a new cache state for synchronization information, and it can make CMPs realize the serial synchronization operation with the way of blocking to guarantee successful execution of atomic operations. Thus, the number of memory accesses caused by synchronization conflicts can be greatly reduced, and an almost perfect memory accessing process in synchronization can be achieved. The experi mental results show that, with the proposed cache coherence protocol, the synchronization performance is almost per- fect. Compared with the traditional cache coherence, the synchronization performance can be increared by 100%, and the whole execution time of parallel programs can be reduced by 25%.