• Title, Summary, Keyword: scheduling

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Distributed Proportional Fair Scheduling for Wireless LANs (무선 LAN을 위한 분산화된 비례공정 스케줄링)

  • Park, Hyung-Kun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.12
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    • pp.2262-2264
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    • 2007
  • In this paper, we propose a distributed opportunistic scheduling scheme for wireless LAN network. Proportional fair scheduling is one of the opportunistic scheduling schemes and used for centralized networks, whereas we design distributed proportional fair scheduling (DPFS). In the proposed DPFS scheme, each receiver estimates channel condition and calculates independently its own priority with probabilistic manner, which can reduce excessive probing overhead required to gather the channel conditions of all receivers. We evaluate the proposed DPFS using extensive simulation and simulation results show that DPFS obtains up to 23% higher throughput than conventional scheduling schemes and has a flexibility to control the fairness and throughput by controlling the system parameter.

An IPC-based Dynamic Cooperative Thread Array Scheduling Scheme for GPUs

  • Son, Dong Oh;Kim, Jong Myon;Kim, Cheol Hong
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.2
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    • pp.9-16
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    • 2016
  • Recently, many research groups have focused on GPGPUs in order to improve the performance of computing systems. GPGPUs can execute general-purpose applications as well as graphics applications by using parallel GPU hardware resources. GPGPUs can process thousands of threads based on warp scheduling and CTA scheduling. In this paper, we utilize the traditional CTA scheduler to assign a various number of CTAs to SMs. According to our simulation results, increasing the number of CTAs assigned to the SM statically does not improve the performance. To solve the problem in traditional CTA scheduling schemes, we propose a new IPC-based dynamic CTA scheduling scheme. Compared to traditional CTA scheduling schemes, the proposed dynamic CTA scheduling scheme can increase the GPU performance by up to 13.1%.

A Virtual-Queue based Backpressure Scheduling Algorithm for Heterogeneous Multi-Hop Wireless Networks

  • Jiao, Zhenzhen;Zhang, Baoxian;Zheng, Jun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.12
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    • pp.4856-4871
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    • 2015
  • Backpressure based scheduling has been considered as a promising technique for improving the throughput of a wide range of communication networks. However, this scheduling technique has not been well studied for heterogeneous wireless networks. In this paper, we propose a virtual-queue based backpressure scheduling (VQB) algorithm for heterogeneous multi-hop wireless networks. The VQB algorithm introduces a simple virtual queue for each flow at a node for backpressure scheduling, whose length depends on the cache size of the node. When calculating flow weights and making scheduling decisions, the length of a virtual queue is used instead of the length of a real queue. We theoretically prove that VQB is throughput-optimal. Simulation results show that the VQB algorithm significantly outperforms a classical backpressure scheduling algorithm in heterogeneous multi-hop wireless networks in terms of the packet delivery ratio, packet delivery time, and average sum of the queue lengths of all nodes per timeslot.

Distributed Multimedia Scheduling in the Cloud

  • Zheng, Mengting;Wang, Wei
    • Journal of Multimedia Information System
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    • v.2 no.1
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    • pp.143-152
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    • 2015
  • Multimedia services in the cloud have become a popular trend in the big data environment. However, how to efficiently schedule a large number of multimedia services in the cloud is still an open and challengeable problem. Current cloud-based scheduling algorithms exist the following problems: 1) the content of the multimedia is ignored, and 2) the cloud platform is a known parameter, which makes current solutions are difficult to utilize practically. To resolve the above issues completely, in this work, we propose a novel distributed multimedia scheduling to satisfy the objectives: 1) Develop a general cloud-based multimedia scheduling model which is able to apply to different multimedia applications and service platforms; 2) Design a distributed scheduling algorithm in which each user makes a decision based on its local information without knowing the others' information; 3) The computational complexity of the proposed scheduling algorithm is low and it is asymptotically optimal in any case. Numerous simulations have demonstrated that the proposed scheduling can work well in all the cloud service environments.

Dynamic Task Scheduling Via Policy Iteration Scheduling Approach for Cloud Computing

  • Hu, Bin;Xie, Ning;Zhao, Tingting;Zhang, Xiaotong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.3
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    • pp.1265-1278
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    • 2017
  • Dynamic task scheduling is one of the most popular research topics in the cloud computing field. The cloud scheduler dynamically provides VM resources to variable cloud tasks with different scheduling strategies in cloud computing. In this study, we utilized a valid model to describe the dynamic changes of both computing facilities (such as hardware updating) and request task queuing. We built a novel approach called Policy Iteration Scheduling (PIS) to globally optimize the independent task scheduling scheme and minimize the total execution time of priority tasks. We performed experiments with randomly generated cloud task sets and varied the performance of VM resources using Poisson distributions. The results show that PIS outperforms other popular schedulers in a typical cloud computing environment.

Acquisition and Refinement of State Dependent FMS Scheduling Knowledge Using Neural Network and Inductive Learning (인공신경망과 귀납학습을 이용한 상태 의존적 유연생산시스템 스케쥴링 지식의 획득과 정제)

  • 김창욱;민형식;이영해
    • Journal of Intelligence and Information Systems
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    • v.2 no.2
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    • pp.69-83
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    • 1996
  • The objective of this research is to develop a knowledge acquisition and refinement method for a multi-objective and multi-decision FMS scheduling problem. A competitive neural network and an inductive learning algorithm are integrated to extract and refine necessary scheduling knowledge from simulation outputs. The obtained scheduling knowledge can assist the FMS operator in real-time to decide multiple decisions simultaneously, while maximally meeting multiple objective desired by the FMS operator. The acquired scheduling knowledge for an FMS scheduling problem is tested by comparing the desired and the simulated values of the multiple objectives. The result show that the knowledge acquisition and refinement method is effective for the multi-objective and multi-decision FMS scheduling problems.

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Proposition and Evaluation of Parallelism-Independent Scheduling Algorithms for DAGs of Tasks with Non-Uniform Execution Time

  • Kirilka Nikolova;Atusi Maeda;Sowa, Masa-Hiro
    • Proceedings of the IEEK Conference
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    • pp.289-293
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    • 2000
  • We propose two new algorithms for parallelism-independent scheduling. The machine code generated from the compiler using these algorithms in its scheduling phase is parallelism-independent code, executable in minimum time regardless of the number of the processors in the parallel computer. Our new algorithms have the following phases: finding the minimum number of processors on which the program can be executed in minimal time, scheduling by an heuristic algorithm for this predefined number of processors, and serialization of the parallel schedule according to the earliest start time of the tasks. At run time tasks are taken from the serialized schedule and assigned to the processor which allows the earliest start time of the task. The order of the tasks decided at compile time is not changed at run time regardless of the number of the available processors which means there is no out-of-order issue and execution. The scheduling is done predominantly at compile time and dynamic scheduling is minimized and diminished to allocation of the tasks to the processors. We evaluate the proposed algorithms by comparing them in terms of schedule length to the CP/MISF algorithm. For performance evaluation we use both randomly generated DAGs (directed acyclic graphs) and DACs representing real applications. From practical point of view, the algorithms we propose can be successfully used for scheduling programs for in-order superscalar processors and shared memory multiprocessor systems. Superscalar processors with any number of functional units can execute the parallelism-independent code in minimum time without necessity for dynamic scheduling and out-of-order issue hardware. This means that the use of our algorithms will lead to reducing the complexity of the hardware of the processors and the run-time overhead related to the dynamic scheduling.

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Service Prediction-Based Job Scheduling Model for Computational Grid (계산 그리드를 위한 서비스 예측 기반의 작업 스케줄링 모델)

  • Jang Sung-Ho;Lee Jong-Sik
    • Journal of the Korea Society for Simulation
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    • v.14 no.3
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    • pp.91-100
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    • 2005
  • Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes a service prediction-based job scheduling model and present its scheduling algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts the next processing time of each processing component and distributes a job to a processing component with minimum processing time. This paper implements the job scheduling model on the DEVS modeling and simulation environment and evaluates its efficiency and reliability. Empirical results, which are compared to conventional scheduling policies, show the usefulness of service prediction-based job scheduling.

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Schedulability Test using task utilization in Real-Time system (실시간 시스템에서 태스크 이용율을 이용한 스케줄링 가능성 검사)

  • Lim Kyung-Hyun;Seo Jae-Hyeon;Park Kyung-Woo
    • Journal of Internet Computing and Services
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    • v.6 no.2
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    • pp.25-35
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    • 2005
  • The Rate Monotonic(RM) scheduling algorithm and Earliest Deadline First(EDF) scheduling algorithm are normally used in Real-Time scheduling algorithm. In those scheduling algorithm, we could predict the performance possibility with total utilization value of task group. But. it had problems with prediction of the boundedness in individual task when the utilization value was over in temporary task. In this paper, the suggested scheduling algorithm can predict task when the utilization value was over and it suggested the method of predicting scheduling possibility based on the utilization value of individual task as well. it predicted the boundedness of scheduling possibility test through simulation In Real-Time scheduling algorithm and analyzed the result.

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Worst-case Guaranteed Scheduling Algorithm for HR-WPAN (HR-WPAN을 위한 Worst-case Guaranteed Scheduling Algorithm)

  • Kim, Je-Min;Lee, Jong-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.5B
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    • pp.270-276
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    • 2007
  • The proposed LDS(Link-status Dependent Scheduling) algorithm in HR-WPAN(High Rate-Wireless Personal Area Network) up to now aims at doing only throughput elevation of the whole network, when the crucial device is connected with worst-link relatively, throughput of this device becomes aggravation. The proposed the WGS(Worst-case Guaranteed Scheduling) algorithm in this paper guarantees throughput of the device which is connected with worst-link in a certain degree as maintaining throughput of all devices identically even if a link-status changes, decreases delay of the whole network more than current LDS algorithm. Therefore proposed WGS algorithm in this paper will be useful in case of guaranteeing throughput of a device which is connected worst-link in a certain degree in a design of HR-WPAN hereafter.