The Quest for a Zero Overhead Parallel Machine

这个项目的主要目标是证明成本有效的并行计算技术的可行性，使计算无处不在的两个应用领域。 第一种是并行数据库，它体现了数据挖掘/数据仓库应用中使用的客户机/服务器范式。 第二个是虚拟多媒体环境的物理模拟，在日常生活中有潜在的用途。 在这个领域的挑战是执行逼真的物理模拟在真实的时间的多个演员（一些真实的和一些合成），每个有几个自由度。 本研究将探讨系统架构的问题，在设计的并行（集群）服务器与商品处理和网络组件，以支持这些应用程序。 从编程此类应用程序的角度来看，跨集群的共享地址空间是一个有吸引力的抽象。 然而，从集群中观察到的延迟方面来看，从这个共享地址空间访问和缓存数据可能是昂贵的。 因此，隐藏访问共享地址空间的通信开销的巧妙技术对于实现良好的性能至关重要。 最终目标是使集群服务器看起来好像应用程序的通信开销为零。 本研究中要解决的具体研究问题包括：（a）实现跨集群共享地址空间的机制;（B）支持可变粒度、缓存、显式通信和同步的机制（在共享空间的框架内）适合这些应用的需要，（c）硬件辅助，使集群作为具有成本效益的并行机具有吸引力，及（d）群集服务器在此类多媒体和数据库工作量下的详细性能评估。

The primary goal of this project is to demonstrate the viability of cost- effective parallel computing techniques for two application domains that make computing ubiquitous. The first one is parallel databases embodying a clients/server paradigm used in data mining/data warehousing applications. The second one is the physical simulation of virtual multimedia environments that has potential use in several everyday situations. The challenge in this domain is to perform realistic physical simulation in real time of multiple actors (some real and some synthetic), each with several degrees of freedom. This research will investigate the system architecture issues in the design of parallel (cluster) servers engineered with commodity processing and network components for supporting such applications. A shared address space across the cluster is an attractive abstraction from the perspective of programming such applications. However, accessing and caching data from this shared address space can be expensive in terms of observed latencies in a cluster. Therefore, clever techniques that hide the communication overheads for accessing the shared address space are imperative to achieving good performance. The ultimate goals is to make the cluster server appear as though the applications incur zero overhead for communication. Specific research issues to be addressed in this research include (a) mechanisms for realizing shared address space across the cluster, (b) mechanisms for supporting variable granularity, caching, explicit communication, and synchronization (within the framework of shared space) tailored to the needs of these applications, (c) hardware assists necessary to make clusters appealing as cost-effective parallel machines, and (d) detailed performance evaluations of cluster servers under such multimedia and database workloads.