Allocation of periodic tasks with precedences on transputer-based systems

Task allocation is an important component of the process of mapping modules of application programs to multicomputers. A scheme for static allocation of periodic tasks with precedences to processors is developed considering task execution times, communication costs, and utilization level of each processor. It has the main goal of minimizing the application response time with a minimum number of processors. A network of transputers is employed as a platform to experimentally evaluate the allocation approach constructed with this work. An existing communication layer in the language ADA is improved to provide an efficient support for task flow simulations on transputer networks. The first phase of the allocation scheme is a constructive assignment heuristic that allocates the cluster of tasks composed of all tasks in the critical path in the same processor. The remaining tasks are allocated according to a heuristic function that considers task precedences, task execution times, and relative sizes of intertask messages. The initial allocation is improved in the second phase by using an iterative pairwise interchange of tasks that considers interprocessor communication distances. The overall scheme of task allocation was successfully tested and analyzed through simulation of several applications on a transputer network providing a near optimal solution.http://archive.org/details/allocationofperi00falcLieutenant Commander, Brazilian NavyApproved for public release; distribution is unlimited

Dynamic resource allocation in a hierarchical multiprocessor system: A preliminary study

An integrated system approach to dynamic resource allocation is proposed. Some of the problems in dynamic resource allocation and the relationship of these problems to system structures are examined. A general dynamic resource allocation scheme is presented. A hierarchial system architecture which dynamically maps between processor structure and programs at multiple levels of instantiations is described. Simulation experiments were conducted to study dynamic resource allocation on the proposed system. Preliminary evaluation based on simple dynamic resource allocation algorithms indicates that with the proposed system approach, the complexity of dynamic resource management could be significantly reduced while achieving reasonable effective dynamic resource allocation

Implementing PRISMA/DB in an OOPL

PRISMA/DB is implemented in a parallel object-oriented language to gain insight in the usage of parallelism. This environment allows us to experiment with parallelism by simply changing the allocation of objects to the processors of the PRISMA machine. These objects are obtained by a strictly modular design of PRISMA/DB. Communication between the objects is required to cooperatively handle the various tasks, but it limits the potential for parallelism. From this approach, we hope to gain a better understanding of parallelism, which can be used to enhance the performance of PRISMA/DB.\ud The work reported in this document was conducted as part of the PRISMA project, a joint effort with Philips Research Eindhoven, partially supported by the Dutch "Stimuleringsprojectteam Informaticaonderzoek (SPIN)