Research Of Memory Management Technique Based On Page Coloring In Multi-core Operating Systems

Multi-core architectures greatly improve the performance that one chip can provide, but this makes the "Memory Wall" problem more and more severe. Memory is a very important shared resource in multi-core architectures. The contention on such shared resouces usually brings negative influence. In such cases, the performance of the memory system is affected, and it is more difficult to analyze and predict the timing behavior of the system. Therefore, to improve multi-core system performance and analysis precision, it is important to put special focus on new memory management techniques.Isolation is a widely adopted principle in management of shared resources. Page Coloring is an effective software level solution for management of shared Caches that implements this idea. Traditional DRAM management techniques are mostly work on the hardware level, and the main approaches is choosing the best address mapping by studying the behavior of the program to improve the performance of DRAM accesses. Usually improving the parallelism between BANKs and reducing the conflicts in the Row-Buffer are two main mechanisms to improve performance.This paper integrates the characteristics of these studies, and proposes a way to enhance DRAM performance which uses Page Coloring technique on software level. The paper’s main tasks are as follows. Firstly, exploring how to statistic a program’s DRAM requests in OS environment. Secondly, designing a new memory management with Page Coloring technique based on Linux-2.6.20kernel. And setting up and configuring the experiment platform with Simics and GEMS. Thirdly, making experiment with two type programs. At last, summarizing this paper and pointing out the lack of design. Be ready for the future work.In this thesis, a new Page Coloring based software DRAM management technique is proposed to improve the performance of memory systems, which combines the characteristics of the above two research. First, we explored how to calculate the number of accesses to DRAM that each virtual address may generate, based on which the information that can guide Page Coloring is extracted. Second, we extended the memory management module of Linux-2.6.20kernel with our Page Coloring based technique, and designed a set of color management structures. Experiments were conducted on a simulation platform constructed on Simics and GEMS. We have conducted experiments on both data intensive applications and computation intensive appliations. The results show that the Page Coloring based DRAM management technique proposed in this thesis can effectively isolation inter-core conflicts, and then greatly improves overall system performance. The performance gain is more prominent for data intensive applications.