Michael O. Neary

Javelin: Internet-based parallel computing using Java

The JAVM (Java Astra Virtual Machine) project is about harnessing the immense computational resource available in the Internet for parallel processing. In this paper, the suitability of Java for Internet-based parallel computing is explored. Next, existing implementations of systems that make use of Java for network parallel computing are presented and categorized. A critique of these implementations follows. Basing on the critique, the requirements and goals of an effective parallel computing system in the Internet environment are singled out. These serve as the blueprint for the development of the JAVM system. Its infrastructure and features, namely ease of use, heterogeneity, portability, security, fault tolerance, load balancing, scalability and accountability, are discussed. Lastly, experimental results based on the running of several parallel applications in the JAVM environment are presented. Basing on the results, the kind of parallel applications that would be well suited for running in JAVM are identified.

Javelin++: scalability issues in global computing

Javelin is a Java-based infrastructure for global computing. This paper presents Javelin++, an extension of Javelin, intended to support a much larger set of computational hosts. First, Javelin++‘s switch from Java applets to Java applications is explained. Then, two scheduling schemes are presented: a probabilistic work-stealing scheduler and a deterministic scheduler. The deterministic scheduler also implements eager scheduling, as well as another fault-tolerance mechanism for hosts that have failed or retreated. A Javelin++ API is sketched, then illustrated on a raytracing application. Performance results for the two schedulers are reported, indicating that Javelin++, with its broker network, scales better than the original Javelin.

Javelin: parallel computing on the internet

Abstract Java offers the basic infrastructure needed to integrate computers connected to the Internet into a seamless distributed computational resource: an infrastructure for running coarse-grained parallel applications on numerous, anonymous machines. First, we sketch such a resource’s essential technical properties. Then, we present a prototype of Javelin , an infrastructure for global computing. The system is based on Internet software that is interoperable, increasingly secure, and ubiquitous: Java-enabled Web technology. Ease of participation is seen as a key property for such a resource to realize the vision of a multiprocessing environment comprising thousands of computers. Javelin’s architecture and implementation require participants to have access to only a Java-enabled Web browser. Experimental results are given in the form of a Mersenne Prime application and a ray-tracing application that run on a heterogeneous network of several parallel machines, workstations, and PCs. Two key areas of current research, fault-tolerance and scalability, are subsequently explored briefly.

Javelin 2.0: Java-Based Parallel Computing on the Internet

This paper presents Javelin 2.0. It presents architectural enhancements that facilitate aggregating larger sets of host processors. It then presents: a branch-and-bound computational model, the supporting architecture, a scalable task scheduler using distributed work stealing, a distributed eager scheduler implementing fault tolerance, and the results of performance experiments. Javelin 2.0 frees application developers from concerns about complex interprocessor communication and fault tolerance among Internetworked hosts. When all or part of their application can be cast as a piecework or a branch-and-bound computation, Javelin 2.0 allows developers to focus on the underlying application.

Advanced eager scheduling for Java-based adaptive parallel computing

Javelin 3 is a software system for developing large‐scale, fault‐tolerant, adaptively parallel applications. When all or part of their application can be cast as a master–worker or branch‐and‐bound computation, Javelin 3 frees application developers from concerns about inter‐processor communication and fault tolerance among networked hosts, allowing them to focus on the underlying application. The paper describes a fault‐tolerant task scheduler and its performance analysis. The task scheduler integrates work stealing with an advanced form of eager scheduling. It enables dynamic task decomposition, which improves host load‐balancing in the presence of tasks whose non‐uniform computational load is evident only at execution time. Speedup measurements are presented of actual performance on up to 1000 hosts. We analyze the expected performance degradation due to unresponsive hosts, and measure actual performance degradation due to unresponsive hosts. Copyright

Market-based massively parallel Internet computing

Recent advances in Internet connectivity and implementations of safer distributed computing through languages such as Java provide the foundation for transforming computing resources into tradable commodities. We have developed Javelin, a Java-based prototype of a globally distributed heterogeneous, high-performance computational infrastructure that conveniently enables rapid execution of massively parallel applications. Our infrastructure consists of three entities: Hosts, clients, and brokers. Our goal is to allow users to buy and sell computational power using supply and demand, and market mechanisms to marshal computational power far beyond what can be achieved via conventional techniques. Several research issues must be worked out to make this vision a reality: allocating resources between computational objects via market mechanisms; expressing and enforcing scheduling and quality of service constraints; modeling programming in a global computing ecosystem; supporting heterogeneous execution without sacrificing computational speed; ensuring host security; global naming and communication; and client privacy.

Advanced eager scheduling for Java-based adaptively parallel computing

Javelin 3 is a software system for developing large-scale, fault tolerant, adaptively parallel applications. When all or part of their application can be cast as a master-worker or branch-and-bound computation, Javelin 3 frees application developers from concerns about inter-processor communication and fault tolerance among networked hosts, allowing them to focus on the underlying application. The paper describes a fault tolerant task scheduler and its performance analysis. The task scheduler integrates work stealing with an advanced form of eager scheduling. It enables dynamic task decomposition, which improves host load-balancing in the presence of tasks whose non-uniform computational load is evident only at execution time. Speedup measurements are presented of actual performance on up to 1,000 hosts. We analyze the expected performance degradation due to unresponsive hosts, and measure actual performance degradation due to unresponsive hosts.