一种减少长尾延迟的分布式实时约束传播方法  

A Distributed Deadline Propagation Approach to Reduce Long-Tail in Datacenters

作　　者：任睿[1,2] 马久跃[1,2] 隋秀峰[1] 包云岗[1] 

机构地区：[1]中国科学院计算技术研究所,北京100190 [2]中国科学院大学,北京100049

出　　处：《计算机研究与发展》2017年第7期1617-1628,共12页Journal of Computer Research and Development

基　　金：国家自然科学基金国际合作项目(61420106013);国家重点研发计划项目(2016YFB1000201)~~

摘　　要：提出了一种在数据中心环境下用于减少长尾延迟的分布式实时约束传播方法,该方法能够使当前节点感知请求的全局响应时间约束信息,并能够将请求的实时约束信息传播到整个处理路径;节点可以利用请求的实时约束信息进行请求调度或加速请求执行时间,以此来减少长尾延迟现象.同时,针对划分/聚合模式和串行/依赖模式2种数据中心应用,提出了阶段服务模型和并行单元模型,并基于这2种模型实现了分布式实时约束传播框架.最后,在分布式实时约束传播框架上实现了实时约束感知调度算法,通过实验进行了简单的验证,初步的实验结果显示了分布式实时约束传播方法能够在一定程度上减少长尾延迟.Long-tail latency is inevitable and may be amplified for highly modular datacenter applications such as Bing, Facebook, and Amazon＇s retail platform, due to resource sharing, queuing, background maintenance activities, etc. Thus how to tolerate the latency variability in shared environments is crucial in datacenters. This paper proposes a distributed deadline propagation （D2P） approach for datacenter applications to reduce long-tail latency. The key idea of D2P is inspired by the traffic light system in Manhattan, New York City, where one can enjoy a chain of green lights after one stop at a red light, and it allows local nodes to perceive global deadline information and to propagate the information among distributed nodes. Local nodes can leverage the information to do scheduling and adjust processing speed to reduce long-tail latency. Then, we propose stage-service model and parallel-unit model to describe sequential/dependent pattern and partition/aggregate pattern, and implement a distributed deadline propagation framework. At last, based on distributed deadline propagation framework, we use D2P-enabled deadline-aware scheduling algorithm to reduce long-tail latency in our experiments, and the preliminary experimental results show that D2P has the potential of reducing the long-tail latency in datacenters by local nodes leveraging the propagated deadline information.

关 键 词：实时约束传播 长尾延迟 数据中心 划分/聚合模式 串行/依赖模式 

分 类 号：TP302[自动化与计算机技术—计算机系统结构]