一种无目录的共享高速缓存一致性协议
发布时间：2018-08-24 20:31
【摘要】：针对使用目录记录各共享缓存块在各核心的私有备份信息的多核和众核并行系统共享高速缓存一致性协议因使用目录造成性能下降的问题进行了研究。研究发现,实际应用的多核和众核系统可以不存储共享缓存块的共享信息,因为多核和众核系统大都采用弱一致性协议,根据这种协议,某个核心的写操作不需要立即被其他核心观察到,可以延迟到下一个同步点观察到。基于这一发现,提出了一种不用记录共享信息的无目录的(DirectoryLess)共享高速缓存(Shared cache)一致性协议,简称DLS协议。该协议通过在同步点对不确定是否被其他核心更改的缓存块主动无效的方法,在不需要存储共享信息的目录的情况下来保证多核系统符合弱一致性。用并行程序测试集SPLASH-2对一个16核处理器进行了试验,试验结果表明,相比基于目录的MESI协议,DLS不仅可以完全消除目录及其电路面积,而且可平均提高11.08%的程序性能,减少28.83%的片上网络通讯,以及减少15.65%的功耗。而这一切,只需要改变处理器的设计,并不需要改变编程语言和编译器,因此,该协议无需更改或重新编译即可以兼容现有的代码。
[Abstract]:In this paper, the performance degradation caused by using directory to record private backup information of each shared cache block in multi-core and multi-core parallel systems is studied. It is found that practical multi-core and multi-core systems can not store the shared information of the shared buffer block, because most of the multi-core and multi-core systems adopt weak consistency protocol, according to this protocol, A core write operation does not need to be immediately observed by other cores and can be delayed to the next synchronization point. Based on this discovery, a directory free (DirectoryLess) shared cache (Shared cache) conformance protocol (DLS protocol) is proposed. This protocol can guarantee the weak consistency of multi-core systems by initiatively invalidating buffer blocks that are uncertain whether or not they are changed by other cores at the synchronization point without having to store directories with shared information. A 16-core processor is tested with parallel program test set (SPLASH-2). The experimental results show that compared with MESI protocol based on directory, it can not only completely eliminate the directory and its circuit area, but also improve the program performance by 11.08% on average. Reduction of 28.83% in on-chip network communications and 15.65% in power consumption. All this needs to change the design of the processor, not the programming language and compiler, so the protocol can be compatible with existing code without changing or recompiling.
【作者单位】： 计算机体系结构国家重点实验室;中国科学院计算技术研究所;中国科学院研究生院;
【基金】：国家自然科学基金(61100163,61133004,61222204,61221062,61303158,61432016,61472396,61473275) 863计划(2012AA012202) 中国科学院战略性先导科技专项(XDA06010403),中国科学院国际合作(171111KYSB20130002)资助项目
【分类号】：TP333
，
本文编号：2201957
[Abstract]:In this paper, the performance degradation caused by using directory to record private backup information of each shared cache block in multi-core and multi-core parallel systems is studied. It is found that practical multi-core and multi-core systems can not store the shared information of the shared buffer block, because most of the multi-core and multi-core systems adopt weak consistency protocol, according to this protocol, A core write operation does not need to be immediately observed by other cores and can be delayed to the next synchronization point. Based on this discovery, a directory free (DirectoryLess) shared cache (Shared cache) conformance protocol (DLS protocol) is proposed. This protocol can guarantee the weak consistency of multi-core systems by initiatively invalidating buffer blocks that are uncertain whether or not they are changed by other cores at the synchronization point without having to store directories with shared information. A 16-core processor is tested with parallel program test set (SPLASH-2). The experimental results show that compared with MESI protocol based on directory, it can not only completely eliminate the directory and its circuit area, but also improve the program performance by 11.08% on average. Reduction of 28.83% in on-chip network communications and 15.65% in power consumption. All this needs to change the design of the processor, not the programming language and compiler, so the protocol can be compatible with existing code without changing or recompiling.
【作者单位】： 计算机体系结构国家重点实验室;中国科学院计算技术研究所;中国科学院研究生院;
【基金】：国家自然科学基金(61100163,61133004,61222204,61221062,61303158,61432016,61472396,61473275) 863计划(2012AA012202) 中国科学院战略性先导科技专项(XDA06010403),中国科学院国际合作(171111KYSB20130002)资助项目
【分类号】：TP333
，
本文编号：2201957
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