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12
Cost minimization while satisfying hard/soft timing constraints for heterogeneous embedded systems
 ACM Transactions on Design Automation of Electronic Systems (TODAES
, 2009
"... In highlevel synthesis for realtime embedded systems using heterogeneous functional units (FUs), it is critical to select the best FU type for each task. However, some tasks may not have fixed execution times. This article models each varied execution time as a probabilistic random variable and so ..."
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Cited by 14 (6 self)
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In highlevel synthesis for realtime embedded systems using heterogeneous functional units (FUs), it is critical to select the best FU type for each task. However, some tasks may not have fixed execution times. This article models each varied execution time as a probabilistic random variable and solves heterogeneous assignment with probability (HAP) problem. The solution of the HAP problem assigns a proper FU type to each task such that the total cost is minimized while the timing constraint is satisfied with a guaranteed confidence probability. The solutions to the HAP problem are useful for both hard realtime and soft realtime systems. Optimal algorithms are proposed to find the optimal solutions for the HAP problem when the input is a tree or a simple path. Two other algorithms, one is optimal and the other is nearoptimal heuristic, are proposed to solve the general problem. The experiments show that our algorithms can effectively reduce the total cost while satisfying timing constraints with guaranteed confidence probabilities. For example, our algorithms achieve an average reduction of 33.0 % on total cost with 0.90 confidence probability satisfying timing constraints compared with the previous work using worstcase scenario.
Efficient assignment and scheduling for heterogeneous dsp systems
 IEEE Trans. on Parallel and Distributed Systems
, 2005
"... This paper addresses high level synthesis for realtime digital signal processing (DSP) architectures using heterogeneous functional units (FUs). For such special purpose architecture synthesis, an important problem is how to assign a proper FU type to each operation of a DSP application and genera ..."
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Cited by 11 (6 self)
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This paper addresses high level synthesis for realtime digital signal processing (DSP) architectures using heterogeneous functional units (FUs). For such special purpose architecture synthesis, an important problem is how to assign a proper FU type to each operation of a DSP application and generate a schedule in such a way that all requirements can be met and the total cost can be minimized. We propose a twophase approach to solve this problem. In the first phase, we solve heterogeneous assignment problem, i.e., given the types of heterogeneous FUs, a DataFlow Graph (DFG) in which each node has different execution times and costs (may relate to power, reliability, etc.) for different FU types, and a timing constraint, how to assign a proper FU type to each node such that the total cost can be minimized while the timing constraint is satisfied. In the second phase, based on the assignments obtained in the first phase, we propose a minimum resource scheduling algorithm to generate a schedule and a feasible configuration that uses as little resource as possible. We prove heterogeneous assignment problem is NPcomplete. Efficient algorithms are proposed to find an optimal solution when the given DFG is a simple path or a tree. Three other algorithms are proposed to solve the general problem. The experiments show that our algorithms can effectively reduce the total cost compared with the previous work.
Complexity of masterslave tasking on heterogeneous trees
 European Journal of Operational Research
, 2005
"... In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors and network, where processing times and communications times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one r ..."
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Cited by 11 (1 self)
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In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors and network, where processing times and communications times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one receive at a time. In this model, we prove that scheduling on a tree network is NPhard in the strong sense, reducing the problem to the wellknown 3partition problem. 1
Grid Workflow Software for HighThroughput Proteome Annotation Pipeline
 Pipeline”, Life Sciences Grid Workshop Proceedings, Submitted
, 2004
"... Abstract. The goal of the Encyclopedia of Life (EOL) Project is to predict structural information for all proteins, in all organisms. This calculation presents challenges both in terms of the scale of the computational resources required (approximately 1.8 million CPU hours), as well as in data and ..."
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Cited by 5 (1 self)
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Abstract. The goal of the Encyclopedia of Life (EOL) Project is to predict structural information for all proteins, in all organisms. This calculation presents challenges both in terms of the scale of the computational resources required (approximately 1.8 million CPU hours), as well as in data and workflow management. While tools are available that solve some subsets of these problems, it was necessary for us to build software to integrate and manage the overall Grid application execution. In this paper, we present this workflow system, detail its components, and report on the performance of our initial prototype implementation for runs over a largescale Grid platform during the SC’03 conference. 1
Masterslave Tasking on Heterogeneous Processors
 In International Parallel and Distributed Processing Symposium. IEEE Computer
, 2003
"... In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors where communication times and processing times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one receive at a ti ..."
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Cited by 4 (1 self)
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In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors where communication times and processing times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one receive at a time. We propose an algorithm for chains of processors based on an iterative backward construction of the schedule, which is polynomial in the number of processors and in the number of tasks. The complexity is $O(np^2)$ where $n$ is the number of tasks and $p$ the number of processors. We prove this algorithm to be optimal with respect to the makespan. We extend this result to a special kind of tree called spider graphs. ) where n is the number of tasks and p the number of processors. We prove this algorithm to be optimal with respect to the makespan. We extend this result to a special kind of tree called spider graphs.
Parameterized Schedulability Analysis on Uniform Multiprocessors
"... This paper addresses global ratemonotonic scheduling of implicitdeadline periodic realtime tasks on uniform multiprocessor platforms. In particular, we propose new schedulability conditions that include a set of easily computable taskset parameters for achieving better system utilization while ..."
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This paper addresses global ratemonotonic scheduling of implicitdeadline periodic realtime tasks on uniform multiprocessor platforms. In particular, we propose new schedulability conditions that include a set of easily computable taskset parameters for achieving better system utilization while meeting the deadlines of all the tasks. First, an individual sufficient schedulability condition is derived for each task. Then, the collection of schedulability conditions for the tasks are condensed to provide two different simple sufficient schedulability conditions for the entire task system — one for uniform multiprocessors, and one for unitcapacity multiprocessors, respectively. Finally, we show that our proposed simple ratemonotonic schedulability conditions for uniform and unitcapacity multiprocessors have higher worstcase system utilization than all other stateoftheart simple schedulability conditions for global ratemonotonic scheduling of implicitdeadline tasks. 1
Toward a Tool for Scheduling Application Workflows onto Distributed Grid Systems
, 2006
"... In this dissertation, we present a design and implementation of a tool for automatic mapping and scheduling of large scientific application workflows onto distributed, heterogeneous Grid environments. The thesis of this work is that planahead, applicationindependent scheduling of workflow applic ..."
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In this dissertation, we present a design and implementation of a tool for automatic mapping and scheduling of large scientific application workflows onto distributed, heterogeneous Grid environments. The thesis of this work is that planahead, applicationindependent scheduling of workflow applications based on performance models can reduce the turnaround time for Grid execution of the application, reducing burden of Grid application development. We applied the scheduling strategies successfully to Grid applications from the domains of bioimaging and astronomy and demonstrated the effectiveness and efficiency of the scheduling approaches. We also proposed and evaluated a novel scheduling heuristic based on a middleout traversal of the application workflow. A study showed that jobs have to wait in batch queues for a considerable amount of time before they begin execution. Schedulers must consider batch queue waiting times when scheduling Grid applications onto resources with batch queue front ends. Hence, we developed a smart scheduler that considers estimates of batch queue wait
Masterslave Tasking on Heterogeneous Processors
"... In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors where communication times and processing times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one receive at a t ..."
Abstract
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In this paper, we consider the problem of scheduling independent identical tasks on heterogeneous processors where communication times and processing times are different. We assume that communicationcomputation overlap is possible for every processor, but only allow one send and one receive at a time. We propose an algorithm for chains of processors based on an iterative backward construction of the schedule, which is polynomial in the number of processors and in the number of tasks. The complexity is O(np2) where n is the number of tasks and p the number of processors. We prove this algorithm to be optimal with respect to the makespan. We extend this result to a special kind of tree called spider graphs. 1
Efficient Hierarchical SelfScheduling for MPI Applications Executing in Computational Grids
"... The execution of distributed applications on the grid is already a reality. As both the number of applications grow and grids scale, efficient utilization of the available but shared heterogeneous resources will be essential. The EasyGrid middleware is a hierarchically distributed Application Mana ..."
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The execution of distributed applications on the grid is already a reality. As both the number of applications grow and grids scale, efficient utilization of the available but shared heterogeneous resources will be essential. The EasyGrid middleware is a hierarchically distributed Application Management System embedded into MPI applications to facilitate their efficient execution in computational grids. The overhead of employing a distinct AMS to make each application system aware does however bring at least two benefits. First, the (scheduling) policies adopted can be tailored to the specific needs of each application leading to improved performance. Second, distributing the management effort amongst the applications themselves makes grid management more scalable. This paper describes a low intrusion implementation of a hybrid scheduling strategy designed to cope with the dynamic behaviour of grid environments. Using applicationspecific scheduling policies, nearoptimal runtimes highlight the advantages of selfscheduling when executing one or more system aware applications on a grid.