论文标题
使用定时副本,无反馈的负载平衡政策
Load balancing policies without feedback using timed replicas
论文作者
论文摘要
派遣诸如JOIN最短队列(JSQ),最小工作(JSW)及其两个变体的功率等策略用于负载平衡系统中,在这些系统中,瞬时队列长度或所有队列的工作负载信息或其中的一个子集可以查询。在调度程序具有关联内存的情况下,可以通过维护可以派遣作业的空闲服务器列表来最大程度地减少此查询的开销。不需要查询此类信息的最新替代方法包括开始时取消和取消基于完整的复制策略。但是,此类策略的缺点是服务器必须将每个服务的开始或完成与调度员传达,并且必须允许取消冗余副本。实际上,查询消息传递,内存和复制品取消的要求在其实施中构成了挑战,并且其优势尚不清楚。在这项工作中,我们考虑了没有查询加载信息,没有内存的负载平衡策略,并且不要取消副本。令人惊讶的是,与使用服务器反馈信息的一些流行策略相比,我们能够确定此类策略的性能更好的操作制度。我们的政策允许调度员将计时器附加到每个作业或其复制品中。如果其计时器在开始接收服务之前到期,则将其丢弃。我们分析了该政策的几种新颖,易于实施的变体,尽管没有服务器对调度员的反馈,但在某些操作方面的性能也非常出色。
Dispatching policies such as the join shortest queue (JSQ), join smallest work (JSW) and their power of two variants are used in load balancing systems where the instantaneous queue length or workload information at all queues or a subset of them can be queried. In situations where the dispatcher has an associated memory, one can minimize this query overhead by maintaining a list of idle servers to which jobs can be dispatched. Recent alternative approaches that do not require querying such information include the cancel on start and cancel on complete based replication policies. The downside of such policies however is that the servers must communicate the start or completion of each service to the dispatcher and must allow cancellation of redundant copies. In practice, the requirements of query messaging, memory, and replica cancellation pose challenges in their implementation and their advantages are not clear. In this work, we consider load balancing policies that do not query load information, do not have a memory, and do not cancel replicas. Surprisingly, we were able to identify operating regimes where such policies have better performance when compared to some of the popular policies that utilize server feedback information. Our policies allow the dispatcher to append a timer to each job or its replica. A job or a replica is discarded if its timer expires before it starts receiving service. We analyze several variants of this policy which are novel, simple to implement, and also have remarkably good performance in some operating regimes, despite no feedback from servers to the dispatcher.