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arXiv 1503.03128cs.DC
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大规模Parallel Computing中的有效离散复制

Efficient Straggler Replication in Large-scale Parallel Computing

Da Wang, Gauri Joshi, Gregory Wornell

摘要:

在具有许多并行任务的云计算作业中,最慢机器上的任务(离散任务)成为作业完成的瓶颈。MapReduce和Spark等计算框架通过复制分散的任务并等待任何一个副本完成来解决这个问题。尽管在实践中被采用,但很少有关于复制如何影响延迟和额外计算资源成本的分析。在本文中,我们提供了一个框架来分析这种延迟成本权衡,并通过回答设计问题来找到最佳复制策略,例如:1)何时复制离散任务,2)启动多少副本,以及3)是否杀死原始副本。我们的分析表明,对于某些执行时间分布,少量的任务复制可以大大减少延迟以及计算资源的成本。我们还提出了一个算法来估计的延迟和成本的基础上的经验分布的任务执行时间。使用Google集群跟踪中的示例进行的评估表明,与MapReduce中使用的现有复制策略相比,进一步降低了延迟和成本。

英文摘要:

In a cloud computing job with many parallel tasks, the tasks on the slowest machines (straggling tasks) become the bottleneck in the job completion. Computing frameworks such as MapReduce and Spark tackle this by replicating the straggling tasks and waiting for any one copy to finish. Despite being adopted in practice, there is little analysis of how replication affects the latency and the cost of additional computing resources. In this paper we provide a framework to analyze this latency-cost trade-off and find the best replication strategy by answering design questions such as: 1) when to replicate straggling tasks, 2) how many replicas to launch, and 3) whether to kill the original copy or not. Our analysis reveals that for certain execution time distributions, a small amount of task replication can drastically reduce both latency as well as the cost of computing resources. We also propose an algorithm to estimate the latency and cost based on the empirical distribution of task execution time. Evaluations using samples in the Google Cluster Trace suggest further latency and cost reduction compared to the existing replication strategy used in MapReduce.

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。

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