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Efficient algorithms for dynamic allocation of distributed memory

ALGORITHMICA 1999年第2期24卷 139-171页

作者： Leighton, T Schwabe, EJ MIT Dept Math Cambridge MA 02139 USA MIT Comp Sci Lab Cambridge MA 02139 USA Depaul Univ Sch CTI Chicago IL 60604 USA Northwestern Univ Evanston IL 60208 USA

We consider the problem of dynamically allocating and deallocating local memory resources among multiple users in a parallel or distributed system. Given a group of independent users and a collection of interconnected local memory devices, we want to render the fragmentation of the memory resources irrelevant by allowing any user to allocate space for his or her purposes as long as there is space available anywhere in the system. In effect, we would like it to appear to the users as though they are allocating memory from a single central pool of memory, even though the space is distributed throughout the system. Our goal is to devise an on-line allocation algorithm that minimizes two cost measures: first, the fraction? of unused space, which arises due to fragmentation of the memory;second, the slowdown needed by the system to service user requests, which arises due to the contention for access to the memory devices. We solve this distributed dynamic allocation problem in near-optimal Fashion by devising an algorithm that allows the memory to be used to 100% of capacity despite the fragmentation and guarantees that service delays will always be within a constant factor of optimal. The algorithm is completely on-line (no foreknowledge of user activity is assumed) and can accommodate any sequence of allocations and deallocations by the users that does not violate global memory bounds. We also consider the distributed dynamic allocation problem in the more restrictive setting where the local memory devices are connected by a low-degree fixed-connection network, rather than being fully interconnected. In this case, communication costs must be more explicitly considered in our allocation algorithms. We give allocation algorithms for butterfly and hypercube networks, and prove necessary and sufficient conditions on the total amount of memory space needed for near-optimal algorithms to exist.

关键词： dynamic allocation memory allocation parallel and distributed systems allocation algorithms

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SUBCUBE allocation IN HYPERCUBE COMPUTERS

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IEEE TRANSACTIONS ON COMPUTERS 1991年第3期40卷 341-352页

作者： DUTT, S HAYES, JP Dept. of Electr. Eng. & Comput. Sci. Michigan Univ. Ann Arbor MI USA

In hypercube computers that support a multiuser environment, it is important for the operating system to be able to allocate subcubes of different dimensions. Previously proposed subcube allocation schemes, such as the buddy strategy, can fragment the hypercube excessively. We present a precise characterization of the subcube allocation problem and develop a general methodology to solve it. New subcube allocation and coalescing algorithms are described that have the goal of minimizing fragmentation. The concept of a maximal set of subcubes (MSS), which is useful in making allocations that result in a tightly packed hypercube, is introduced. The problems of allocating subcubes and of forming an MSS are formulated as decision problems, and shown to be NP-hard. We prove analytically that the buddy strategy is optimal under restricted conditions, and then show using simulation that its performance is actually poor under more realistic conditions. We suggest a heuristic procedure for efficiently coalescing a released cube with the existing free cubes. This coalescing approach is coupled with a simple best-fit allocation scheme to form the basis of a class of MSS-based strategies that give a substantial performance (hit ratio) improvement over the buddy strategy. Finally, we present simulation results comparing several different allocation and coalescing strategies, which show that our MSS-based schemes provide a marked performance improvement over previous techniques.

关键词： allocation algorithms COALESCING algorithms HYPERCUBE COMPUTERS HYPERCUBE FRAGMENTATION MULTIPROCESSORS NP-COMPLETE PROBLEMS PROCESSOR allocation SUBCUBE PACKING

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Hardware implementation of processor allocation schemes for mesh-based chip multiprocessors

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MICROPROCESSORS AND MICROSYSTEMS 2010年第1期34卷 39-48页

作者： Zydek, Dawid Selvaraj, Henry Univ Nevada Dept Elect & Comp Engn Las Vegas NV 89154 USA

Well-designed Processor Allocator (PA) is an important factor in modern Chip MultiProcessors (CMPs). It needs to be fast as well as area and energy efficient, because it is only a small component of the CMP. In this paper, we propose an architecture for such an efficient and fast PA. The PA structure is based on bit map approach and is driven by an Improved First Fit (IFF) algorithm, which is presented and described. Together with the proposed IFF technique, a new Improved Adaptive Scan (IAS) and an Improved Quick allocation (IQA) algorithms are introduced and discussed and compared with previously known important techniques. The presented synthesis results reveal that the proposed PA achieves good frequency results while, at the same time is characterized by low logic utilization. (C) 2009 Elsevier B.V. All rights reserved.

关键词： CMP Mesh topology Processor allocator allocation algorithms Synthesis Hardware implementation

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Processor allocation Problem for NoC-based Chip Multiprocessors

Processor Allocation Problem for NoC-based Chip Multiprocess...

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6th International Conference on Information Technology - New Generations (ITNG 2009)

作者： Zydek, Dawid Selvaraj, Henry Univ Nevada Dept Elect & Comp Engn Las Vegas NV 89154 USA

ISBN: (纸本)9781424437702

Chip multiprocessors (CMPs) have become the primary approach to build high-performance microprocessors. Such systems require fast and efficient communication that can only be realized using Network on Chip (NoC), particularly for large systems. allocation and management of on-chip processors are also important factors to achieve high efficiency. Designing processor allocator, job scheduler and NoC are major issues for future CMPs. In this paper we analyze architectures of NoC for CMPs. Such NoC parameters as topology, flow control and routing are studied and proposed for CMPs implementation. Modern processor allocation algorithms together with scheduling techniques are reviewed and suggested. Hardware structure of NoC-based CMPs is introduced for the recommended solutions. We propose hardware implementation of processor allocator and job scheduler, and place them together with on-chip processors on the same die.

关键词： allocation algorithms CMPs hardware implementation NoC scheduling techniques

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Optimizing Thermal Energy Sharing in Smart District Heating Networks

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ENERGIES 2024年第12期17卷 2936页

作者： Dattilo, Anna Melino, Francesco Ricci, Mattia Sdringola, Paolo Alma Mater Studiorum Univ Bologna Dept Ind Engn I-40136 Bologna Italy Italian Natl Agcy New Technol Energy & Sustainable Res Ctr Casaccia Energy Efficiency Dept Via Anguillarese 301 I-00123 Rome Italy

The constant attention to sustainability aimed at reconciling economic and social development with environmental protection is the driving force of the continuous growth of renewable energy in the energy sector. Among the numerous actions taken by the European Commission (EC) in this direction, an important initiative towards the complete decarbonization is represented by the Renewable Energy Communities (RECs). According to the EC, "energy communities enable collective and citizen-driven energy actions to support the clean energy transition. They can contribute to increasing public acceptance of renewable energy projects and make it easier to attract private investments in the clean energy transition". At the European level, numerous energy communities are emerging, although they are all based on photovoltaic production and, consequently, focus only on electricity flows. The aim of this paper is to define a thermal energy community in which thermal energy sharing can be achieved by exploiting the concept of the smart district heating network. Starting from a small existing district heating network, its conversion into a smart one will be analyzed and optimized with the aim of studying the sharing of thermal energy between the various prosumer and non-prosumer users connected to the district heating network.

关键词： thermal energy community smart district heating shared energy allocation algorithms

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Cost Benefit Processor: Video allocation Algorithm for Flash-based Solid State Disks

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Procedia - Social and Behavioral Sciences 2012年 46卷 5581-5587页

作者： Jaafer Mohammad Al-Sabateen Saleh Ali Alomari Putra Sumari Multimedia Computing Research Group School of Computer Sciences Universiti Sains Malaysia 11800 USM Pulau Pinang Malaysia

Despite the fact that Solid State Disk (SSD) storage media had offered a revolutionary property storages community, but the unavailability of a comprehensive video allocation strategy in these storage media, had leads to gluttonous consumption of the available space, decreasing the life span among intensive random writing processes, time-consuming reading processes, and unqualified system resources consumption. In order to overcome these challenges, an efficient video allocation algorithm is a desirable and necessary option. In this paper, the authors developed a new video allocation algorithm for flash-based SSDs storage media systems. The Cost Benefit economic concept had been adopted in constructing and developing this algorithm. We called it Cost Benefit Processor (CBP) algorithm. For clarification purposes, the authors had reviewed the internal architecture of it. Some of the default video allocation scenarios are also been discussed. The proposed algorithm had been compared with another allocation algorithm. The comparison results showed the decreasing in both the number of requested blocks and the number of active blocks.

关键词： SSD CBP allocation algorithms Data Management Storage Systems

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Exploiting Local Clouds in the Internet of Everything Environment 23

Exploiting Local Clouds in the Internet of Everything Enviro...

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23rd Euromicro International Conference on Parallel, Distributed, and Network-Based Processing (PDP)

作者： Nieto de Santos, Francisco Javier Garcia Villalonga, Sergio ATOS ATOS Res & Innovat Bilbao Spain

ISBN: (纸本)9781479984909

The Internet of Everything is opening new opportunities and challenges which will be faced during the following years. Huge amounts of data will be generated and consumed, so Internet of Things frameworks will need to provide new capabilities related to Big Data analysis, scalability and performance. We believe the formation of local clouds of devices, close to the location where data is created and consumed, is a good solution to overcome these issues which may impact in security as well. The combination of local and remote resources together with the appropriate allocation algorithms for their management will provide the means to enable the new required features, going beyond the current state of the art and still leaving enough evolution capacity for future scenarios.

关键词： Mobile Computing Local Clouds Big Data Internet of Everything allocation algorithms

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Towards measurable criteria for the equitable sharing of international water resources

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Water Policy 2002年第1期4卷 19-32页

作者： Van Der Zaag, Pieter Seyam, I.M. Savenije, Hubert H. G. IHE Delft 2601 DA Delft P.O. Box 3015 Netherlands

Equity is key to the allocation of international water resources. Six possible criteria and allocation algorithms that operationalise the equity concept are developed and applied to the Orange Nile and Incomati rivers. The criterion that considers all (blue and green) water resources and that uses the basin population as the main allocation variable yields the most equitable water allocation. Two important variables are identified over which the riparian countries should reach consensus: 1. The value of green water relative to blue water. 2. The fraction of reserved water which is defined as the basic entitlement of each riparian country. These findings are based on approximate data and have therefore a limited validity. With this caveat it is suggested that the approach developed in this article may help de-politicise negotiations between riparian countries and provide fresh perspectives that may unlock stalemates during negotiations. © 2002 Elsevier Science Ltd. All rights reserved.

关键词： allocation algorithms Equity Green water Incomati river International water resources Nile river Orange river Water allocation Water law

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Modeling artificial, mobile swarm systems

Modeling artificial, mobile swarm systems

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作者： Agassounon, William California Institute of Technology

学位级别：Ph.D.

Swarm intelligence is a new research paradigm that offers novel approaches for studying and solving distributed problems using solutions inspired by social insects and other natural behaviors of vertebrates. In this thesis, we present methodologies for modeling artificial mobile systems within the swarm intelligence framework. The proposed methodologies provide guidelines in the study and design of artificial swarm systems for the following two classes of experiments: distributed sensing and distributed manipulation. Event discovery and information dissemination through local communication in artificial swarm systems present similar characteristics as natural phenomena such as foraging and food discovery in insect colonies and the spread of infectious diseases in animal populations, respectively. We show that the artificial systems can be described in similar mathematical terms as those used to describe the natural systems. The proposed models can be classified in two main categories: non-embodied and embodied models. Furthermore, within each category, we distinguish two subcategories: spatial and nonspatial models. In our description of distributed manipulation in swarm robotic systems we present two case studies of non-collaborative and collaborative manipulations, respectively. The general approach proposed here consists of first representing the group behavior of the active agents with a finite state machine then describing mathematically the dynamics of the group. The first case study is the aggregation experiment. We present a macroscopic model that accurately captures the dynamics of the experiment and a suite of threshold-based, scalable, and fully distributed algorithms for allocating the workers to the task optimally. The second case study is that of the stick-pulling experiment. This task requires the collaborative effort of two robots to be successful. Here, we present a discrete-time macroscopic model that helps us uncover counter-intuitive behaviors th

关键词： allocation algorithms collective robotics distributed systems modeling swarm intelligence

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