Abstract-One measure of usefulness of a general-purpose distrib-uted computing system is the system’s ability to provide a level of per-formance commensurate to the degree of multiplicity of resources pres-ent in the system. Many different approaches and metrics of performance have been proposed in an attempt to achieve this goal in existing systems. In addition, analogous problem formulations exist in other fields such as control theory, operations research, and produc-tion management. However, due to the wide variety of approaches to this problem, it is difficult to meaningfully compare different systems since there is no uniform means for qualitatively or quantitatively eval-uating them. It is difficult to successfully build upon existing work or identify areas worthy of additional effort without some understanding of the relationships between past efforts. In this paper, a taxonomy of approaches to the resource management problem is presented in an attempt to provide a common terminology and classification mecha-nism necessary in addressing this problem. The taxonomy, while pre-sented and discussed in terms of distributed scheduling, is also appli-cable to most types of resource management. As an illustration of the usefulness of the taxonomy an annotated bibliography is given which classifies a large number of distributed scheduling approaches accord-ing to the taxonomy. Index Terms-Distributed operating systems, distributed resource management, general-purpose distributed computing systems, sched-uling, task allocation, taxonomy. T I.

This paper argues for the need to design a new processor scheduling algorithm that can handle the mix of applications we see today. We present a scheduling algorithm which we have implemented in the Solaris UNIX operating system [Eykholt et al. 1992], and demonstrate its improved performance over existing schedulers in research and practice on real applications. In particular, we have quantitatively compared against the popular weighted fair queueing and UNIX SVR4 schedulers in supporting multimedia applications in a realistic workstation environment...

We propose a new way for evaluating the performance of packet switching communication networks under a fixed (session based) routing strategy. Our approach is based on properly bounding the probability distribution functions of the system input processes. The bounds we suggest, which are decaying exponentials, possess three convenient properties: When the inputs to an isolated network element are all bounded, they result in bounded outputs, and assure that the delays and queues in this element have exponentially decaying distributions; In some network settings bounded inputs result in bounded outputs; Natural traffic processes can be shown to satisfy such bounds. Consequently, our method enables the analysis of various previously intractable setups. We provide sufficient conditions for the stability of such networks, and derive upper bounds for the interesting parameters of network performance. 1 Introduction In this paper we consider data communication networks, and the problem of ev...

A process is an operating system abstraction representing an instance of a running computer program. Process migration is the act of transferring a process between two machines during its execution. Several implementations

In this paper, we present an adaptive prefetch scheme for network use, in which we download files that will very likely be requested in the near future, based on the user access history and the network conditions. Our prefetch scheme consists of two parts: a prediction module and a threshold module. In the prediction module, we estimate the probability with which each file will be requested in the near future. In the threshold module, we compute the prefetch threshold for each related server, the idea being that the access probability is compared to the prefetch threshold. An important contribution of this paper is that we derive a formula for the prefetch threshold to determine its value dynamically based on system load, capacity, and the cost of time and system resources to the user. We also show that by prefetching those files whose access probability is greater than or equal to its server's prefetch threshold, a lower average cost can always be achieved. As an example, we present a...

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Prefetching is one of the most popular techniques for dealing with the slow access speed of the World Wide Web. To provide a mobile user with effective real time online prefetching requires that the prefetch decision is able to adapt to different network systems. This article describes an adaptive network prefetch scheme which accomplishes this task. The basic scheme is comprised of a prediction module and a threshold module, which computes the access probabilities and prefetch thresholds respectively. The access probabilities indicate how likely files will be requested by the user, and the prefetch thresholds determine whether the performance may be improved by prefetching certain files. As a user changes network in a mobile environment, it is the prefetch threshold, which is computed based on system conditions as well as costs of bandwidth and time, that adjusts the number of prefetched files accordingly. In addition, by extending the method of computing the access probabilities, we are able to prefetch a group of files together for a user who is about to be disconnected from the network.

Int#ra-operator (or partitioned) parallelism is a well-established mechanism for achieving high performance in parallel database systems. However, the problem of how to exploit intra-operator parallelism in a multi-query environment is not well underst,ood. This paper presents a detailed performance evaluation of several algorithms for managing intra-operator parallelism in a parallel database system. A dynamic scheme based on the concept of matching the ra.te of flow of tuples between operat,ors is shown to perform well on a variety of workloads and configurations. 1

Abstract — We explore the feasibility of designing an outdoor cellular network based on the IEEE 802.11 specification. Since the standard is intended for wireless local-area networks (WLAN), there are many technical challenges when applying the air interface to the outdoor environment. We study here how the 802.11 medium access control (MAC) protocol can be applied and how it performs in the outdoor network. By exploiting the fact that timeout intervals are not explicitly specified, without modifying the standard, we propose a new timing structure for the distribution coordination function (DCF) and the handshake of request-to-send (RTS) and clear-to-send (CTS) to handle increased signal propagation delay in the outdoor network. We find that the DCF and RTS/CTS protocols as specified in the standard continue to work properly for a link distance up to 6 km. Our analysis reveals that the DCF performance degrades

Abstract — This paper analyzes a communication network with heterogeneous customers. We investigate priority queueing as a way to differentiate between these users. Customers join the network as long as their utility (which is a function of the queueing delay)is larger than the price of the service. We focus on the specific situation in which two types of users play a role: one type is delay-sensitive (‘voice’), whereas the other is delay-tolerant (‘data’); these preferences are reflected in their utility curves. Two models are considered: in the first the network determines the priority class of the users, whereas the second model leaves this choice to the users. For both models we determine the prices that maximize the provider’s profit. Importantly, these situations do not coincide. Our study uses elements from queueing theory, but also from microeconomics and game theory (e.g., the concept of a Nash equilibrium). We conclude the paper by considering a model in which throughput (rather than delay)is the main performance measure. Again the pricing strategy exploits the heterogeneity in required service and willingness-to-pay. Key words—Packet networks, differentiated services, pricing, congestion, microeconomics, negative externalities, game theory I.