Finishing flows quickly with preemptive scheduling
Finishing flows quickly with preemptive scheduling
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DOI：
10.1145/2342356.2342389
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
C. Hong;M. Caesar;P. B. Godfrey
中科院分区：
文献类型：
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作者：
C. Hong;M. Caesar;P. B. Godfrey
当今的数据中心在提供低延迟方面面临着极大的挑战。然而，公平共享，目前的拥塞控制协议中普遍采用的原则，是远远不能满足延迟要求的最佳。我们提出了抢占式分布式快速（PDQ）流调度，一个协议，旨在快速完成流，满足流的最后期限。PDQ使流抢占接近一系列调度规则。例如，PDQ可以模拟最短作业优先算法，以通过暂停竞争流来给予短流优先级。PDQ借鉴了集中式调度原则的思想，并以完全分布式的方式实现它们，使其可扩展到当今的数据中心。此外，我们开发了一个多路径版本的PDQ利用路径分集。通过大量的数据包级和流级仿真，我们证明了PDQ在数据中心环境中的性能明显优于TCP，RCP和D3。我们进一步表明，PDQ是稳定的，弹性的数据包丢失，并保留几乎所有的性能增益，即使不准确的流量信息。
Today's data centers face extreme challenges in providing low latency. However, fair sharing, a principle commonly adopted in current congestion control protocols, is far from optimal for satisfying latency requirements. We propose Preemptive Distributed Quick (PDQ) flow scheduling, a protocol designed to complete flows quickly and meet flow deadlines. PDQ enables flow preemption to approximate a range of scheduling disciplines. For example, PDQ can emulate a shortest job first algorithm to give priority to the short flows by pausing the contending flows. PDQ borrows ideas from centralized scheduling disciplines and implements them in a fully distributed manner, making it scalable to today's data centers. Further, we develop a multipath version of PDQ to exploit path diversity. Through extensive packet-level and flow-level simulation, we demonstrate that PDQ significantly outperforms TCP, RCP and D3 in data center environments. We further show that PDQ is stable, resilient to packet loss, and preserves nearly all its performance gains even given inaccurate flow information.