Development of distributed real-time applications requires tools and methods ranging from the design process down to the run-time system. This paper describes an approach towards an integrated object-oriented real-tim...
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ISBN:
(纸本)0818680970
Development of distributed real-time applications requires tools and methods ranging from the design process down to the run-time system. This paper describes an approach towards an integrated object-oriented real-time environment, providing a new conceptual structuring method, distributed dynamic scheduling, and a real-time executive, based on a standard real-time operating system. TaskPairs are introduced as a method for structuring distributed object-oriented applications that consist of a mix of hard-, soft- and non-real-time jobs. From this language level structure the compiler and a run-time monitor create an abstract representation of the system's objects, their dependencies, and their actual timing behavior. Based on this information about the current system state the distributedresourcemanagement dynamically tries to construct a feasible schedule.
We consider the problem of mapping video algorithms onto systems of high-performance video signal processors with hard real-time constraints. The mapping problem under consideration is computationally hard due to the ...
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ISBN:
(纸本)0818680970
We consider the problem of mapping video algorithms onto systems of high-performance video signal processors with hard real-time constraints. The mapping problem under consideration is computationally hard due to the many constraints that need to be satisfied. We present a compact mathematical formulation which identifies the decision variables and the constraints that are involved. We demonstrate that the mapping problem is NP-hard in the strong sense. The insight resulting from the mathematical formulation leads to a solution approach in which the problem is decomposed into subproblems called delay management, partitioning, and scheduling. These subproblems are handled with well-known techniques from the literature such as network flow, local search, and constraint satisfaction.
The most important goal in hard real-time systems is to guarantee that all timing constraints are satisfied. Even though object-based techniques (which contain reusable software components) are used to manage the comp...
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ISBN:
(纸本)0818680970
The most important goal in hard real-time systems is to guarantee that all timing constraints are satisfied. Even though object-based techniques (which contain reusable software components) are used to manage the complexity in the software development process of such systems, execution efficiency may have to be sacrificed, due to the large number of procedure calls and contention for accessing software components. These issues are addressed by the following parallelizing technique: (a) converting potentially inefficient procedure calls to a source of concurrency via asynchronous remote procedure calls (ARPC) (b) replicating (or cloning) software components to reduce the contention. The existing object-based scheduling algorithms construct an initial schedule and apply incremental parallelization techniques to modify the initial schedule till a feasible schedule is generated. But these algorithms are applicable for scheduling only multiple independent tasks. This paper describes a pre-run-time scheduling algorithm for a set of periodic object-based tasks having precedence constraints among them. The algorithm employs parallelism exploitation techniques to guarantee timeliness in almost fully predictable environments such as factory automation, aerospace, and avionics. It allocates the components of object-based periodic tasks to the sites of a distributed system based on a clustering heuristic which takes into account the ARPC parallelism and load balancing, and schedules them on respective sites. The algorithm also finds a schedule for communication channel(s) and clones the components of object-based periodic tasks, if contention occurs in accessing them. In addition to the above (periodicity and precedence) constraints, the tasks handled by our algorithm can have resource constraints among them. The experimental evaluation of the algorithm shows that the combination of the proposed clustering heuristic and cloning enhances schedulability.
Advanced general-purpose parallelsystems should be able to support diverse applications with different resource requirements without compromising effectiveness and efficiency. We present a new resourcemanagement mod...
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Advanced general-purpose parallelsystems should be able to support diverse applications with different resource requirements without compromising effectiveness and efficiency. We present a new resourcemanagement model for cluster computing that allows multiple scheduling policies to co-exist dynamically. In particular, we have built Octopus, an extensible and distributed hierarchical scheduler that implements new space-sharing, gang-scheduling and load-sharing strategies. A series of experiments performed on an IBM SP2 suggest that Octopus can effectively match application requirements to available resources, and improve the performance of a variety of parallel applications within a cluster.
A significant amount of research for developing a software environment for parallel computers is being performed. The research efforts are classified into three categories: compilers, languages and support tools. One ...
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A significant amount of research for developing a software environment for parallel computers is being performed. The research efforts are classified into three categories: compilers, languages and support tools. One of the most important support tools for parallel and distributed computing are the resourcemanagement tools. These tools enable the system to realize its the maximum utilization with the proper management of processors, communication channels and I/O devices. The goal of partitioning and scheduling schemes is to efficiently partition the application into several tasks and assign the individual onto the various processors of the system.
Clusters of workstations are increasingly being viewed as a cost-effective alternative to parallel supercomputers. However, resourcemanagement and scheduling on workstations clusters is complicated by the fact that t...
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Clusters of workstations are increasingly being viewed as a cost-effective alternative to parallel supercomputers. However, resourcemanagement and scheduling on workstations clusters is complicated by the fact that the number of idle workstations available for executing parallel applications is constantly fluctuating. In this paper, we present a case for schedulingparallel applications on non-dedicated workstation clusters using dynamic space-sharing, a policy under which the number of processors allocated to an application can be changed during its execution. We describe an approach that uses application-level checkpointing and data repartitioning for supporting dynamic space-sharing and for handling the dynamic reconfiguration triggered when failure or owner activity is detected on a workstation being used by a parallel application. The performance advantages of dynamic space-sharing are quantified through a simulation study, and experimental results are presented for the overhead of dynamic reconfiguration of a grid-oriented data parallel application using our approach.
parallelization of image analysis tasks forms a basic key for processing huge image data in real time. At this, suitable subtasks for parallel processing have to be extracted and mapped to components of a distributed ...
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Dynamic resource allocation, particularly in the form of processorpar-titioning and scheduling, is an important factor in achieving good utilization and high performance in multiprocessor systems. We are developing a ...
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Development of distributed real-time applications requires tools and methods ranging from the design process down to the run-time system. This paper describes an approach towards an integrated object-oriented real-tim...
详细信息
Development of distributed real-time applications requires tools and methods ranging from the design process down to the run-time system. This paper describes an approach towards an integrated object-oriented real-time environment, providing a new conceptual structuring method, distributed dynamic scheduling, and a real-time executive, based on a standard real-time operating system. TaskPairs are introduced as a method for structuring distributed object-oriented applications that consist of a mix of hard-, soft- and non-real-time jobs. From this language level structure the compiler and a run-time monitor create an abstract representation of the system's objects, their dependencies, and their actual timing behaviour. Based on this information about the current system state the distributedresourcemanagement dynamically tries to construct a feasible schedule.
Advanced general purpose parallelsystems should be able to support diverse applications with different resource requirements without compromising effectiveness and efficiency. We present a resourcemanagement model f...
详细信息
Advanced general purpose parallelsystems should be able to support diverse applications with different resource requirements without compromising effectiveness and efficiency. We present a resourcemanagement model for cluster computing that allows multiple scheduling policies to co-exist dynamically. In particular, we have built Octopus, an extensible and distributed hierarchical scheduler that implements new space sharing, gang scheduling and load sharing strategies. A series of experiments performed on an IBM SP2 suggest that Octopus can effectively match application requirements to available resources, and improve the performance of a variety of parallel applications within a cluster.
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