Efficient Replication of Queued Tasks to Reduce Latency in Cloud Systems
Efficient Replication of Queued Tasks to Reduce Latency in Cloud Systems
复制标题
有效复制排队任务以减少云系统中的延迟
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Gauri Joshi
中科院分区：
文献类型：
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作者：
Gauri Joshi
-在云计算系统中，将作业分配给多个服务器并等待最早完成的副本是解决单个服务器响应时间变化的有效方法。虽然增加冗余副本总能缩短服务时间，但每个作业花费的总计算时间可能会更长，从而增加排队等待时间。每个作业花费的总时间也与计算资源成本成正比。我们分析了不同的冗余策略（如副本数量、发布和取消副本的时间）对延迟和计算成本的影响。我们发现，服务时间分布的对数凹性是决定增加冗余是否能减少延迟和成本的关键因素。如果服务时间分布是对数凸的，那么增加最大冗余就能减少延迟和成本。而如果是对数凸，那么减少副本数量并尽早取消冗余请求会更有效。
—In cloud computing systems, assigning a job to multiple servers and waiting for the earliest copy to finish is an effective method to combat the variability in response time of individual servers. Although adding redundant replicas always reduces service time, the total computing time spent per job may be higher, thus increasing waiting time in queue. The total time spent per job is also proportional to the cost of computing resources. We analyze how different redundancy strategies, for eg. number of replicas, and the time when they are issued and canceled, affect the latency and computing cost. We get the insight that the log-concavity of the service time distribution is a key factor in determining whether adding redundancy reduces latency and cost. If the service distribution is log-convex, then adding maximum redundancy reduces both latency and cost. And if it is log-concave, then having fewer replicas and canceling the redundant requests early is more effective.