异构集群下的MapReduce编程环境

吴承勇 崔慧敏

摘 要：该报告针对Godson-D的芯片特征和亿级并发负载的特征，研究了层次化MapReduce编程模型，对上层应用呈现简洁的编程接口，并利用OpenCL来开发Godson-D芯片的计算能力。对其中的3个关键问题进行了阐述：形成了完整的层次化MapReduce编程模型的框架，并实现了原型系统，旨在解决现有MapReduce模型在多核/众核芯片组成的集群中存在的性能墙、在适用场景方面存在的无法适应增量式分析这两个主要的问题；为了解决Godson-D上的编程困难问题，该研究提出使用OpenCL编写程序，并配套开发CPU+Godson-D异构系统中OpenCL编译/运行时系统的解决方案。在该研究中，首先完成了OpenCL编译/运行时支持系统的框架设计，该框架采用层次化设计思想，分为功能层、优化层、平台层；多核/众核处理器及云计算被认为将会统治计算领域的未来，多核/众核处理器在目前的云计算数据中心中被广泛采用，但是目前其资源利用率非常低，主要原因在于核间性能干扰的存在，使得数据中心的调度程序不得不禁止关键应用的co-location来保证QoS，为此，提出了一种基于统计学习的多核间性能干扰分析方法，可以量化地分析任意程序遭受的核间性能干扰，并根据干扰模型提高资源的利用率。

关键词：异构集群 编程环境 异构芯片 编译技术

Abstract：Based on the chip architecture and the features of highly concurrent workloads， this report discussed the hierarchical MapReduce programming model， to expose a user-friendly programming interface and leverage OpenCL to take advantange of the computing power of Godson-D processor. This report presented three key ideas in detail：（1） Existing MapReduce programming model has two disadvantages： it cannot take advantage of the computing power of underlying multi/many-core processors， and it cannot adapt for increamental analysis. To address these two problems， we proposed the hierarchical MapReduce programming framework implements a prototype.（2） To provide a user-friendly programming interface for Godson-D， we proposed a OpenCL compiler/runtime system for Godson-D. We designed a hierarchical hetergeneous compiler/runtime system for Godson-D， which includes functional level， optimization level and platform level.（3） Despite their widespread adoption in cloud computing， multicore processors are heavily under-utilized in terms of computing resources. To avoid the potential for negative and unpredictable interference， co-location of a latency-sensitive application with others on the same multicore processor is disallowed， leaving many cores idle and causing low machine utilization. To enable co-location while providing QoS guarantees， it is challenging but important to predict performance interference between co-located applications.We proposed a regression approach to predict the interference and improve the resource utilization.

Key Words：Hertergeneous clusters；Programming enviornment；Hetergeneous chip；Compiler

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