Accelerating two-dimensional page walks for virtualized systems

Nested paging is a hardware solution for alleviating the software memory management overhead imposed by system virtualization. Nested paging complements existing page walk hardware to form a two-dimensional (2D) page walk, which reduces the need for hypervisor intervention in guest page table management. However, the extra dimension also increases the maximum number of architecturally-required page table references. This paper presents an in-depth examination of the 2D page table walk overhead and options for decreasing it. These options include using the AMD OpteronTM processor's page walk cache to exploit the strong reuse of page entry references. For a mix of server and SPEC R benchmarks, the presented results show a 15%38% improvement in guest performance by extending the existing page walk cache to also store the nested dimension of the 2D page walk. Caching nested page table translations and skipping multiple page entry references produce an additional 3%-7% improvement. Mu...

• Type: Conference
• Year: 2008
• Where: ASPLOS
• Authors: Ravi Bhargava, Ben Serebrin, Francesco Spadini, Srilatha Manne
• Keywords: ASPLOS 2008, Page Entry References, Page Table, Page Walk, Programming Languages