Desperately Seeking ... Optimal Multi-Tier Cache Configurations
Desperately Seeking ... Optimal Multi-Tier Cache Configurations
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发表时间：
2020
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通讯作者：
Tyler Estro;Pranav Bhandari;Avani Wildani;E. Zadok
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作者：
Tyler Estro;Pranav Bhandari;Avani Wildani;E. Zadok
现代缓存层次结构是复杂性的网站。具有许多可配置参数的异质物理和虚拟设备的多个层次均认为在本地应用程序和远程应用程序之间最佳地提供一群请求。有效设计这些系统的挑战因硬件，固件，高速缓存驱动算法的创新以及不断发展的工作负载和访问模式而加剧。这个快速扩展的配置空间使其昂贵且耗时，以便对许多稳定的工作负载进行大量的缓存配置。当前的缓存评估技术（例如，错过比率曲线）是短视的：他们仅分析一个缓存，主要关注性能，并且未能检查诸如吞吐量和货币成本之类的指标之间的关键关系。公开可用的I/O缓存模拟器也缺乏：它们只能模拟固定或有限数量的缓存层，缺少关键功能或提供有限的分析。我们的立场是，缓存分析中的最佳实践应包括评估多层配置，再加上更全面的指标，这些指标揭示了关键的设计权衡，尤其是货币成本。我们正在开发一个n级I/O缓存模拟器，该模拟器足以建模任何缓存层次结构，捕获许多指标，提供了一组强大的分析功能，并且易于扩展以促进实验性研究或生产水平提供。为了证明我们提出的指标和模拟器的价值，我们扩展了现有的缓存模拟器（Pymimircache）。在本文中，我们提出了一些有趣且违反直觉的结果。
Modern cache hierarchies are tangled webs of complexity. Multiple tiers of heterogeneous physical and virtual devices, with many configurable parameters, all contend to optimally serve swarms of requests between local and remote applications. The challenge of effectively designing these systems is exacerbated by continuous advances in hardware, firmware, innovation in cache eviction algorithms, and evolving workloads and access patterns. This rapidly expanding configuration space has made it costly and time-consuming to physically experiment with numerous cache configurations for even a single stable workload. Current cache evaluation techniques ( e.g. , Miss Ratio Curves) are short-sighted: they analyze only a single tier of cache, focus primarily on performance, and fail to examine the critical relationships between metrics like throughput and monetary cost. Publicly available I/O cache simulators are also lacking: they can only simulate a fixed or limited number of cache tiers, are missing key features, or offer limited analyses. It is our position that best practices in cache analysis should include the evaluation of multi-tier configurations, coupled with more comprehensive metrics that reveal critical design trade-offs, especially monetary costs. We are developing an n -level I/O cache simulator that is general enough to model any cache hierarchy, captures many metrics, provides a robust set of analysis features, and is easily extendable to facilitate experimental research or production level provisioning. To demonstrate the value of our proposed metrics and simulator, we extended an existing cache simulator (PyMimircache). We present several interesting and counter-intuitive results in this paper.