ISMB:多核系统中利用 Bank 分区实现共享库隔离-《计算机技术与发展》

文章信息/Info

Title:: ISMB:Isolation of Shared Libraries in MultiCore Systems via Bank Partitioning

Author(s):: YANG Hu-bin; LI Jia-xiang; CHEN Yu-cong; LIU Gang; ZHANG Hong-tao; ZHOU Rui; ZHOU Qing-guo; School of Information Science and Engineering,Lanzhou University,Lanzhou 730000,China

Keywords:: hared library; Bank partitioning; isolation; DRAM; Bank row buffer conflict

摘要:: 动态随机存取存储器 DRAM 一直以来以其低功耗、高性价比和良好的扩展性等优点作为计算机内存的最佳选择。为了提高内存的访问速度,DRAM 中的每个 Bank 都有一个行缓冲区,它可以有效地提升局部性良好的应用程序的性能。然而在多核系统中,DRAM 被系统中的所有 Core 共享,因此对内存的并发访问会导致 Bank 行缓冲区冲突问题的产生,从而导致内存访问延迟的增大。共享库作为一种共享资源,使 Bank 行缓冲区冲突问题更加严重。虽然目前有一些基于DRAM Bank 分区技术的解决方案可以有效缓解由进程访问私有内存导致的 Bank 行缓冲区冲突问题,但是这些解决方案无法解决访问共享库引起的 Bank 行缓冲区冲突问题。该文提出了一种在多核系统中利用 Bank 分区实现共享库隔离的方案(ISMB) 。 ISMB 使运行在同一个 Core 上的进程只能访问属于该 Core 的共享库的副本,因此 ISMB 消除了共享库导致的 Bank 行缓冲区冲突问题。对比实验结果表明, ISMB 能够有效地提升系统隔离性能, 在使用 ISMB 的情况下, SPECCPU2006 基准测试程序的减速率最大可降低 26. 3% 。

Abstract:: Dynamic Random Access Memory ( DRAM ) has always been the best choice of memory device due to its low powerconsumption,high performance-price ratio and good scalability. To improve memory access speed,each Bank in DRAM has a row bufferthat can effectively improve the performance of programs with good locality. However,the DRAM memory is shared by all Cores onMultiCore systems,so concurrent access to memory can lead to Bank row buffer conflict,resulting in increased memory access latency.As a shared resource,shared library makes the problem worser. Although there are some solutions based on DRAM Bank partitioning technology that can effectively alleviate the Bank row buffer conflict caused by the access to private date,the conflict caused by accessingthe shared libraries has not been completely solved. In this paper,we propose ISMB,a new mechanism which realizes the isolation ofshared library on MultiCore system by using Bank partition technology. ISMB allows all processes running on the same Core to accessthe copies of shared libraries that belong to this Core,so ISMB can eliminate the Bank row buffer conflicts caused by shared libraries.The experimental results demonstrate that ISMB is effective in improving the performance isolation,the slowdown ratios of the SPECCPU2006 benchmarks can be reduced by up to 26. 3% by using ISMB.