Proceedings of the 5th Symposium on Operating Systems Design and Implementation Practical, Transparent Operating System Support for Superpages
Proceedings of the 5th Symposium on Operating Systems Design and Implementation Practical, Transparent Operating System Support for Superpages
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通讯作者：
Juan E. Navarro;Sitaram Iyer;P. Druschel;Alan L. Cox
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作者：
Juan E. Navarro;Sitaram Iyer;P. Druschel;Alan L. Cox
大多数通用处理器都提供对大尺寸内存页面（称为超级页面）的支持。超级页面使转换后备缓冲区 (TLB) 中的每个条目能够将大的物理内存区域映射到虚拟地址空间。这极大地增加了 TLB 覆盖范围，减少了 TLB 缺失，并有望提高许多应用程序的性能。然而，支持超级页面给操作系统带来了一些挑战，如超级页面分配和升级权衡、碎片控制等。我们分析了这些问题，并提出了一种有效的超级页面管理系统的设计。我们在 FreeBSD 的 Alpha CPU 上实现它，并根据实际工作负载和基准对其进行评估。我们获得了显着的性能优势，通常超过 30%；即使在工作负载紧张的情况下，这些好处也能持续存在。
Most general-purpose processors provide support for memory pages of large sizes, called superpages. Su-perpages enable each entry in the translation lookaside buffer (TLB) to map a large physical memory region into a virtual address space. This dramatically increases TLB coverage, reduces TLB misses, and promises performance improvements for many applications. However , supporting superpages poses several challenges to the operating system, in terms of superpage allocation and promotion tradeoffs, fragmentation control, etc. We analyze these issues, and propose the design of an effective superpage management system. We implement it in FreeBSD on the Alpha CPU, and evaluate it on real workloads and benchmarks. We obtain substantial performance benefits, often exceeding 30%; these benefits are sustained even under stressful workload scenarios.