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MULTI-PROGRAMMING AND MEMORY CONTENTION

SOFTWARE-PRACTICE & EXPERIENCE 1980年第7期10卷 531-552页

作者： SMITH, AJ Computer Science Division Department of Electrical Engineering and Computer Sciences and the Electronics Research Laboratory University of California Berkeley California 94720 U.S.A.

We study memory contention during multiprogramming when programs are free to compete for page frames. A random walk between the possible partitions of memory over the set of active programs is used to model memory contention and calculate throughput. Our model of contention takes into account program characteristics by using miss ratio curves, and also considers memory size and page fetch latency. With the aid of numerous trace-driven simulations, we are able to verify our model, finding good agreement both in the observed distribution of memory among competing programs and in CPU utilization. We find that for high ratios of secondary to primary memory access time and under conditions of high memory contention, small programs with compact working sets are able to run with far less than expected interference from larger, more diffuse programs. In the case of multiprogramming the same program several times, we find that observed partition distributions are not necessarily even and that higher than expected levels of CPU use are observed. Lower ratios of access time are found to yield different results; programs compete on a more even basis and partition memory relatively more evenly than with higher ratios.

关键词： multiprogramming Memory contention Paging LRU Memory management Virtual memory Memory technology Program behaviour Global LRU

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IMPLEMENTATION OF STRUCTURED MULTI-PROGRAMMING

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SOFTWARE-PRACTICE & EXPERIENCE 1978年第3期8卷 313-322页

作者： BEAUMONT, WP Department of Computing Science University of Adelaide Adelaide South Australia 5001

The study of operating systems principles is greatly enhanced if processes can be expressed in language constructs that explicitly allow for multiprogramming. The enhancement is increased if such a system actually exists for practical use. This paper describes an implementation of such a system. The language used (a forerunner of Concurrent Pascal) is described briefly. The body of the paper describes the implementation method in some detail. In order to achieve multiprogramming with a single processor, a number of process descriptors are maintained, each associated with the execution point in the program of a parallel process. Control is distributed among the processes in a manner determined by the program environment. The design of the implementation, in itself, provides an interesting example of operating systems principles at work.

关键词： multiprogramming Structured programming Concurrent programming Parallel Pascal Simulation

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GENERATING-FUNCTION ANALYSIS OF MULTI-PROGRAMMING QUEUES

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INTERNATIONAL JOURNAL OF COMPUTER & INFORMATION SCIENCES 1978年第2期7卷 121-155页

作者： HOFRI, M

A simple MP system consisting of an input-output facility and a central processor is modeled as a two-parameter Markov chain. The conditions for stability are demonstrated, and the steady-state joint probabilities are calculated explicitly. Various priority and capacity assignments result in radically different analytical situations, some of which have been considered in the literature. The present work treats a version that was considered for a time intractable. This paper emphasizes the analytical properties of the probability-generating functions and a method to solve a resultant functional equation. The numerical results display the importance of dependence between variables in the model.

关键词： multiprogramming networks probability-generating functions Queues queues in a loop steady-state behavior two-dimensional random walk two-server queueing systems

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RANDOM INJECTION CONTROL OF MULTI-PROGRAMMING IN VIRTUAL MEMORY

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1978年第1期4卷 2-17页

作者： GELENBE, E KURINCKX, A D?partement de Mathematiques Universit? Paris-Nord

We propose a new method for the control of a multiprogrammed virtual memory computer system. A mathematical model solved by decomposition permits us to justify that the method avoids thrashing. Simulation experiments are used to test the robustness of the predictions of the mathematical model when certain simplifying assumptions are relaxed and when a slightly simpler control technique based on the same principle is used. Comparisons are given with the case where an "optimal" control is used and with that with no control. We also provide a simulation evaluating the estimators used in an implementation of the control, as well as the responsiveness of the controlled system to transients in the workload.

关键词： Virtual Memory multiprogramming

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SCHEDULING HEURISTICS IN A MULTI-PROGRAMMING ENVIRONMENT

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IEEE TRANSACTIONS ON COMPUTERS 1978年第7期27卷 628-637页

作者： APPELBE, WF ITO, MR UNIV BRITISH COLUMBIA DEPT COMP SCIVANCOUVER V6T 1W5BCCANADA UNIV BRITISH COLUMBIA DEPT ELECT ENGNVANCOUVER V6T 1W5BCCANADA

Utilization of a uniprocessor system in a multiprogramming environment can be optimized by maximizing the overlap of processor and input-output operations. A computational process can be modeled by a directed graph each node of which represents a task comprising processor and input-output segments. Any optimal schedulng algorithm for the model cannot be polynomially bounded, but the optimal criteria can be used to develop a hierarchy of dispatching heuristics based upon selecting an optimal partial task schedule. These heuristics are analyzed and evaluated by a simulation study and are shown to be more effective than those previously proposed. The dispatching heuristics developed have a wide range of potential applications to systems requiring dynamic task scheduling.

关键词： multiprogramming partial sequence scheduling heuristics sequence dominance task task segment

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DISTRIBUTED PROCESS CREATION WITHIN A SHARED DATA SPACE FRAMEWORK

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SOFTWARE-PRACTICE & EXPERIENCE 1995年第2期25卷 175-191页

作者： ROBINSON, PG ARTHUR, JD The Department of Computer Sciences Virginia Tech Blacksburg VA 24060 U.S.A.

This paper describes the design and implementation of a remote process instantiation mechanism which is consistent with the Linda paradigm and semantics of the EVAL operation, and which uses shared data space as the medium for passing process and environment parameters. The motivation for such an implementation stems from our effort to rehost a uniprocessor version of the Linda computational system to a network of workstations. The baseline version of the Linda system relies on the semantics of the UNIX fork () system call to create processes and to pass the proper execution parameters to them. In creating a distributed version of the Linda environment, two major issues are addressed: (1) how to instantiate a remote process that knows where, among several possibilities, to begin its execution, and (2) how to communicate the proper run-time values of relevant variables to each new remote Linda process. Guiding our implementation was a desire to employ existing interprocess communication facilities, i.e. shared data space, to pass process creation and execution parameters.

关键词： multiprogramming

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SCHEDULING SUPPORT FOR CONCURRENCY AND PARALLELISM IN THE MACH OPERATING SYSTEM

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COMPUTER 1990年第5期23卷 35-43页

作者： BLACK, DL Carnegie Mellon Univ. Pittsburgh PA

The shared use of general-purpose uniprocessors is examined. Support for common uniform-memory-access architectures that have all memory equidistant from all processors in terms of access time is emphasized. This work is also applicable to non-uniform-memory-access machines, whose memory access times depend on the physical distance between the processor and the accessed memory, but it does not provide a complete solution to load-balancing problems for this class of machine. The discussion covers time-sharing scheduling, the Mach scheduler, programming models, scheduling concurrency support, processor allocation, and related work

关键词： Mach operating system Mach scheduler common uniform-memory-access architectures concurrency support general-purpose uniprocessors memory access times multiprogramming operating systems (computers) parallelism processor allocation programming models scheduling time-sharing scheduling

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Adaptive thresholding and dynamic windowing method for automatic centroid detection of digital Shack-Hartmann wavefront sensor

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APPLIED OPTICS 2009年第32期48卷 6088-6098页

作者： Yin, Xiaoming Li, Xiang Zhao, Liping Fang, Zhongping Singapore Inst Mfg Technol Singapore 638075 Singapore

A Shack-Hartmann wavefront sensor (SWHS) splits the incident wavefront into many subsections and transfers the distorted wavefront detection into the centroid measurement. The accuracy of the centroid measurement determines the accuracy of the SWHS. Many methods have been presented to improve the accuracy of the wavefront centroid measurement. However, most of these methods are discussed from the point of view of optics, based on the assumption that the spot intensity of the SHWS has a Gaussian distribution, which is not applicable to the digital SHWS. In this paper, we present a centroid measurement algorithm based on the adaptive thresholding and dynamic windowing method by utilizing image processing techniques for practical application of the digital SHWS in surface profile measurement. The method can detect the centroid of each focal spot precisely and robustly by eliminating the influence of various noises, such as diffraction of the digital SHWS, unevenness and instability of the light source, as well as deviation between the centroid of the focal spot and the center of the detection area. The experimental results demonstrate that the algorithm has better precision, repeatability, and stability compared with other commonly used centroid methods, such as the statistical averaging, thresholding, and windowing algorithms. (C) 2009 Optical Society of America

关键词： adaptive thresholding spot intensity surface profile measurement window method Hartmann-Shack wavefront sensor multiprogramming Centroid Gaussian distribution central area

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Constant complexity scheduling for hardware multitasking in two dimensional reconfigurable field-programmable gate arrays

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IET COMPUTERS AND DIGITAL TECHNIQUES 2008年第6期2卷 401-412页

作者： Roman, S. Mecha, H. Mozos, D. Septien, J. Univ Complutense Madrid Dept Arquitectura Comp & Automat E-28040 Madrid Spain

Technological improvements achieved for reconfigurable hardware together with applications' increasing demand of flexibility and speed for complex applications, make run-time reconfigurable devices an interesting piece in the design of computing systems. Operating systems ( OS) have to be extended with functionalities, which allow them to efficiently manage the field-programmable gate arrays (FPGA). A constant-complexity algorithm is presented that would be a part of such an extended OS. The algorithm decides the scheduling and placing of arrival tasks with real-time constraints in the FPGA device. It divides the FPGA area into four partitions of different sizes. Each partition has an associated queue where the hardware manager places each arriving task depending on its size, shape and real time parameters as deadline requirements. The algorithm may change the queue selection policy, partition strategies and the sizes or the number of partitions at run-time in order to adapt itself in function of special characteristics of task profiles, taking into account task sizes and execution times for tasks in each queue. The authors will present experimental results, which prove that our algorithm is as competitive as other complex 'area-greedy' algorithms for real applications with real-time deadline constraints.

关键词： scheduling two dimensional reconfigurable field-programmable gate arrays hardware multitasking run-time reconfigurable devices FPGA multiprogramming queue selection policy operating systems (computers) operating systems field programmable gate arrays constant complexity scheduling

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AN ALGORITHM FOR STATE-SPACE FREQUENCY-DOMAIN IDENTIFICATION WITHOUT WINDOWING DISTORTIONS

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1994年第9期39卷 1880-1885页

作者： BAYARD, DS Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA

An algorithm is presented for identifying state-space models from frequency-domain data. The main advantage of this approach is that it avoids windowing distortions associated with other frequency-domain methods. Other advantages are that an arbitrary frequency weighting can be introduced to shape the estimation error, and the system order can be overspecified. The numerical properties are demonstrated on real physical data taken on a complex flexible structure, leading to the successful identification of a multivariable (four-input/three-output) 100-state model over a bandwidth of 100 Hertz. The results indicate that the algorithm would be useful in applications requiring the accurate identification of high-order systems over wide bandwidths.

关键词： algorithms Higher-order system Bandwidth frequency weighting multiprogramming Frequency domain identification

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