英特尔页面修改日志，一项硬件虚拟化功能：研究和改进虚拟机工作集估计
Intel Page Modification Logging, a hardware virtualization feature: study and improvement for virtual machine working set estimation
摘要：
英特尔页面修改日志记录（PML）是一项新颖的硬件功能，用于跟踪虚拟机（VM）访问的内存页面。这项任务在当今的数据中心中至关重要，因为它允许检查点、实时迁移和工作集大小（WSS）估计等。本文以Xen虚拟机管理程序为依托，从功耗、效率和对用户应用程序性能影响三个角度研究PML。我们的调查结果如下。首先，PML不会产生任何功耗开销。其次，PML将VM实时迁移和检查点设置时间减少了10.18%。第三，PML可以将实时迁移和检查点所导致的应用程序性能下降降低0.95%。第四，然而，PML不允许准确的WSS估计，因为不跟踪读取访问并且不能识别热页。为解决这些限制而对PML进行的简单扩展可能会导致计算WSS的VM的性能严重下降（高达34.8%）。本文介绍了页面引用日志（PRL），一个智能扩展的PML允许读取和写入访问进行跟踪。这样做不会影响用户VM。本文还提出了一个WSS估计系统，利用PRL，并展示了如何将该算法集成到一个数据中心，实现内存超量使用。我们实现PRL和WSS估计系统下，Gem5，一个非常流行的硬件模拟器。评估结果验证了PRL在WSS估计中的准确性。他们还表明，PRL不会导致用户虚拟机的性能下降。
英文摘要：
Intel Page Modification Logging (PML) is a novel hardware feature for tracking virtual machine (VM) accessed memory pages. This task is essential in today's data centers since it allows, among others, checkpointing, live migration and working set size (WSS) estimation. Relying on the Xen hypervisor, this paper studies PML from three angles: power consumption, efficiency, and performance impact on user applications. Our findings are as follows. First, PML does not incur any power consumption overhead. Second, PML reduces by up to 10.18% both VM live migration and checkpointing time. Third, PML slightly reduces by up to 0.95% the performance degradation on applications incurred by live migration and checkpointing. Fourth, PML however does not allow accurate WSS estimation because read accesses are not tracked and hot pages cannot be identified. A naive extension of PML for addressing these limitations could lead to severe performance degradation (up to 34.8%) for the VM whose WSS is computed. This paper presents Page Reference Logging (PRL), a smart extension of PML for allowing both read and write accesses to be tracked. It does this without impacting user VMs. The paper also presents a WSS estimation system which leverages PRL and shows how this algorithm can be integrated into a data center which implements memory overcommitment. We implement PRL and the WSS estimation system under Gem5, a very popular hardware simulator. The evaluation results validate the accuracy of PRL in the estimation of WSS. They also show that PRL incurs no performance degradation for user VMs.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
