We measure the distribution of lifetimes for UNIX processes and propose a functional form that fits this distribution well. We use this functional form to derive a policy for preemptive migration, and then use a trace-driven simulator to compare our proposed policy with other preemptive migration policies, and with a non-preemptive load balancing strategy. We find that, contrary to previous reports, the performance benefits of preemptive migration are significantly greater than those of non-preemptive migration, even when the memorytransfer cost is high. Using a model of migration costs representative of current systems, we find that preemptive migration reduces the mean delay (queueing and migration) by 35 -- 50%, compared to non-preemptive migration. 1 Introduction Most systems that perform load balancing use remote execution (i.e. non-preemptive migration) based on a priori knowledge of process behavior, often in the form of a list of process names eligible for migration. Althoug...

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This research investigates the problem of allocating a set of heterogeneous applications to a set of heterogeneous machines connected together by a high-speed network. The proposed resource allocation heuristics were implemented on the High Performance Distributed Computing Program's (HiPer-D) Naval Surface Warfare Center testbed. The goal of this study is to design static resource allocation heuristics that balance the utilization of the computation and network resources while ensuring very low failure rates. A failure occurs if no allocation is found that allows the system to meet its resource and quality of service constraints. The broader goal is to determine an initial resource allocation that maximizes the time before run-time re-allocation is required for managing an increased workload. This study proposes two heuristics that perform well with respect to the loadbalancing and failure rates. These heuristics are, therefore, very desirable for HiPer-D like systems where low failure rates can be a critical requirement.

by Karen Marie Tracey A processor sharing system allows busy users in a networked environment to take advantage of the processing power of idle machines. Experimental systems have demonstrated the usefulness of the concept, but processor sharing has yet to achieve widespread acceptance. Simplistic sharing policies and programming difficulty are two factors that combine to limit the use and acceptance of processor sharing. Group management, a new approach to processor sharing presented here, addresses these problems. Group management is designed to support processor sharing applications that consist of multiple cooperating tasks. This new approach provides a framework for the development of sophisticated sharing policies that can support a variety of applications with differing execution characteristics. In addition, it provides services to programmers that ease the task of writing programs for, and running programs in, a processor sharing environment. This dissertation introduces group...

A runtime support is necessary for parallel computations with irregular and dynamic structures. One important component in the support system is the runtime scheduler which balances the working load in the system. We present a new algorithm, Symmetrical Hopping, for dynamic scheduling of ultra-lightweight processes. It is a dynamic, distributed, adaptive, and scalable scheduling algorithm. This algorithm is described and compared to four other algorithms that have been proposed in this context, namely the randomized allocation, the sender-initiated scheduling, the receiver-initiated scheduling, and the gradient model. The performance of these algorithms on Intel Touchstone Delta is presented. The experimental results show that the Symmetrical Hopping algorithm achieves much better performance due to its adaptiveness. 1. Introduction Large distributed memory parallel machines are becoming increasingly available. To efficiently use such large machines to solve an application problem, th...

Networking computers has provided a great potential for performance improvement of job execution through dynamic load balancing. In effect, the literature on this subject concludes that dynamic load balancing algorithms can significantly reduce jobs waiting time. The application of these encouraging results onto real systems has proven to be difficult due to the complexity, lack of support, and lack of adequate software tools for constructing distributed load balancing systems This paper presents the design, implementation and a performance analysis of a dynamic load balancing system. The performance evaluation is undertaken using an Office Information System (OIS) as a case study. The dynamic load balancing prototype has been developed using a distributed programming model which supports dynamic configuration. It is argued that this latter exhibits capabilities that are essential for a system operating in a changing and evolving environment. The overall system has been implemented an...

Dynamic load sharing policies have been extensively studied. Most of the previous studies have assumed a homogeneous distributed system with a first-come-first-served (FCFS) node scheduling policy. In addition, job service times and inter-arrival times are assumed to be exponentially distributed. In this paper, we study the impact of these assumptions on the performance of sender-initiated and receiver-initiated dynamic load sharing policies in heterogeneous distributed systems. We consider two node scheduling policies - first-come/first-served (FCFS) and round robin (RR) policies. Furthermore, the impact of variance in inter-arrival times and job service times is studied. Our results show that, even in heterogeneous distributed systems, when the round robin node scheduling policy is used, senderinitiated policy is better than the receiver-initiated policy unless the variance in job service times is low. This is an important observation as most workstations use a scheduling policy simi...

Load sharing is a technique to improve the performance of distributed systems by distributing the system workload from heavily loaded nodes to lightly loaded nodes in the system. Previous studies have considered two adaptive load sharing policies: sender-initiated and receiver-initiated. In the sender-initiated policy, a heavily loaded node attempts to transfer work to a lightly loaded node and in the receiver-initiated policy a lightly loaded node attempts to get work from a heavily loaded node. Most of the previous studies have assumed the first-come/first-served (FCFS) node scheduling policy; furthermore, analyses and simulations in these studies have been done under the assumption that the job service times are exponentially distributed and the job arrivals form a Poisson process. The goal of this paper is to fill the void in the existing literature. We study the impact of these assumptions on the performance of the sender-initiated and receiverinitiated policies. We consider thre...

This report contains the results of the graduation project for the Computer Science course at the University of Amsterdam. The work for the project was done within the Information & Communication Service department at Shell Research, Amsterdam (Koninklijke/ShellLaboratorium, Amsterdam), where I have been employed since 1985. Professor Dr. L.O. Hertzberger, Dr. P.M.A. Sloot, Dr. P. van Emde Boas (University of Amsterdam) and Dr. P.A.J. van Deurzen (Shell Research, Amsterdam) were the supervisors. The initial goal of the project, defined in the spring of 1992, was to explore to what extent distributed systems could contribute to a more efficient use of the networked workstations installed at KSLA (Koninklijke/Shell-Laboratorium, Amsterdam). Follows some initial problems in defining the scope of the project, the idea was born to use PVM and Condor - two available packages supporting distributed computing - to run an existing scientific application. This would pave the way for a test with the DCE (Distributed Computing Environment) products from OSF (Open Software Foundation). However, partially due to personnel movement the test with the scientific application had to be postponed. The results of this study are: - a rudimentary form of DYNAMICPVM which combines PVM and Condor, - a better understanding of the impact the introduction of distributed systems will have on the KSLA organisation. I would like to thank Professor Hertzberger, who put me on the right track, Peter Sloot, who kept me on the track and Paul van Deurzen who patiently guided me past many obstacles during the project and had his interrupt bit turned off for me. A. de Beer, Th. Breet, R.P. Bosma and G. Noordenbos have provided me royally, on behalf of Shell, with all the facilities I required for this course...

One of the challenges in programming distributed memory parallel machines is deciding how to allocate work to processors. This problem is particularly important for computations with unpredictable dynamic behaviors or irregular structures. We present a scheme for dynamic scheduling of medium-grained processes that is useful in this context. The Adaptive Contracting Within Neighborhood (ACWN) is a dynamic, distributed, load-dependent, and scalable scheme. It deals with dynamic and unpredictable creation of processes, and adapts to different systems. The scheme is described and contrasted with two other schemes that have been proposed in this context, namely the randomized allocation and the gradient model. The performance of the three schemes on an Intel iPSC/2 hypercube is presented and analyzed. The experimental results show that even though the ACWN algorithm incurs somewhat larger overhead than the randomized allocation, it achieves better performance in most cases due to its adapti...