Can I/O Variability Be Reduced on QoS-Less HPC Storage Systems?
Can I/O Variability Be Reduced on QoS-Less HPC Storage Systems?
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DOI：
10.1109/tc.2018.2881709
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发表时间：
2019-05
影响因子：
3.7
通讯作者：
Dan Huang;Qing Liu;J. Choi;N. Podhorszki;S. Klasky;Jeremy S. Logan;G. Ostrouchov;Xubin He;M. Wolf
中科院分区：
文献类型：
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作者：
Dan Huang;Qing Liu;J. Choi;N. Podhorszki;S. Klasky;Jeremy S. Logan;G. Ostrouchov;Xubin He;M. Wolf
对于生产高性能计算（HPC）系统，在多个应用程序之间共享存储设备并以最佳努力进行管理，I/O的争论通常是一个主要问题。在本文中，我们提出了一个基于平衡的消息传递的重新布置，并在中间件级别的限制结合使用。这项工作解决了过去尚未完全解决的两个关键挑战：无需QoS的HPC存储系统可以降低I/O的可变性，以及如何设计运行时调度系统，该系统可以扩展到大量扩展到大量内核。所提出的方案使用两级消息传递系统将I/O请求重新布置到一个不那么拥挤的存储位置，从而改善了写入性能，同时限制了通过限制重新路由对阅读的影响。得出一个分析模型以指导最佳节流因子的设置。我们彻底分析了虚拟消息传递层开销，并探索透射缓冲是否有效地管理I/O变异性。与直觉相反，传播缓冲区无法完全解决该问题。它可以降低绝对可变性，但不能降低相对可变性。针对合成基准和生产应用程序使用的拟议方案将得到验证。
For a production high-performance computing (HPC) system, where storage devices are shared between multiple applications and managed in a best effort manner, I/O contention is often a major problem. In this paper, we propose a balanced messaging-based re-routing in conjunction with throttling at the middleware level. This work tackles two key challenges that have not been fully resolved in the past: whether I/O variability can be reduced on a QoS-less HPC storage system, and how to design a runtime scheduling system that can scale up to a large amount of cores. The proposed scheme uses a two-level messaging system to re-route I/O requests to a less congested storage location so that write performance is improved, while limiting the impact on read by throttling re-routing. An analytical model is derived to guide the setup of optimal throttling factor. We thoroughly analyze the virtual messaging layer overhead and explore whether the in-transit buffering is effective in managing I/O variability. Contrary to the intuition, in-transit buffer cannot completely solve the problem. It can reduce the absolute variability but not the relative variability. The proposed scheme is verified against a synthetic benchmark as well as being used by production applications.