Dynamic, heterogeneous and distributively owned resource environments present unique challenges to the problems of resource representation, allocation and management. Conventional resource management methods that rely on static models of resource allocation policy and behavior fail to address these challenges. We previously argued that Matchmaking provides an elegant and robust solution to resource management in such dynamic and federated environments. However, Matchmaking is limited by its purely bilateral formalism of matching a single customer with a single resource, precluding more advanced resource management services such as co-allocation. In this paper, we present Gangmatching, a multilateral extension to the Matchmaking model, and discuss the Gangmatching model and its associated implementation and performance issues in context of a real-world license management co-allocation problem.

Federated distributed systems present new challenges to resource management, which cannot be met by conventional systems that employ relatively static resource models and centralized allocators. We previously argued that matchmaking provides an elegant and robust resource management solution for these highly dynamic environments (R. Raman et al., 1998). Although powerful and flexible, multiparty policies (e.g., co-allocation) cannot be accommodated by matchmaking. The authors present Gang-Matching, a multilateral matchmaking formalism to address this deficiency.

Conventional resource management systems use a system model to describe resources and a centralized scheduler to control their allocation. We argue that this paradigm does not adapt well to distributed systems, particularly those built to support high throughput computing. Obstacles include heterogeneity of resources, which make uniform allocation algorithms difficult to formulate, and distributed ownership, leading to widely varying allocation policies. Faced with these problems, we developed and implemented the classified advertisement (classad) matchmaking framework, a flexible and general approach to resource management in distributed environment with decentralized ownership of resources. Novel aspects of the framework include a semi structured data model that combines schema, data, and query in a simple but powerful specification language, and a clean separation of the matching and claiming phases of resource allocation. The representation and protocols result in a robust, scalable and flexible framework that can evolve with changing resources. The framework was designed to solve real problems encountered in the deployment of Condor, a high throughput computing system developed at the University of Wisconsin-Madison. Condor is heavily used by scientists at numerous sites around the world. It derives much of its robustness and efficiency from the matchmaking architecture.

An important problem faced by many database management systems is the "online object placement problem"--the problem of choosing a disk page to hold a newly allocated object. In the absence of clustering criteria, the goal is to maximize storage utilization. For main-memory based systems, simple heuristics exist that provide reasonable space utilization in the worst case and excellent utilization in typical cases. However, the storage management problem for databases includes significant additional challenges, such as minimizing I/O traffic, coping with crash recovery, and gracefully integrating space management with locking and logging.We survey several object placement algorithms, including techniques that can be found in commercial and research database systems. We then present a new object placement algorithm that we have designed for use in Shore, an object-oriented database system under development at the University of Wisconsin--Madison. Finally, we present results from a series of experiments involving actual Shore implementations of some of these algorithms. Our results show that while current object placement algorithms have serious performance deficiencies, including excessive CPU or main memory overhead, I/O traffic, or poor disk utilization, our new algorithm consistently excellent performance in all of these areas.

Persistent object-oriented applications that traverse large object graphs can improve their performance by caching objects in main memory while they are being used. While caching offers large performance benefits, the techniques used to locate these cached objects in memory can still impede the application's performance. We present the results of a trace-based simulation study of pointer swizzling techniques (techniques for reducing the cost of access to cached objects). We used traces derived from actual persistent programs to find a class of swizzling techniques that performs well, yet permits changes to the contents of in-memory object caches over the lifetime of an application. Our study demonstrates the superiority of a class of techniques known as "indirect swizzling" for a variety of workloads and system configurations.>

SHORE (Scalable Heterogeneous Object REpository) is a persistent object system under development at the University of Wisconsin. SHORE represents a merger of object-oriented database and file system technologies. In this paper we give the goals and motivation for SHORE, and describe how SHORE provides features of both technologies. We also describe some novel aspects of the SHORE architecture, including a symmetric peer-to-peer server architecture, server customization through an extensible value-added server facility, and support for scalability on multiprocessor systems. An initial version of SHORE is already operational, and we expect a release of Version 1 in mid-1994.

In traditional interactive programming environments, each application individually manages its interaction with the human user. The result is duplication of effort in implementing user interface code and nonuniform—hence confusing—input conventions. This paper presents an approach to support automatic generation of user interfaces in environments based on algebraic languages. The approach supports the editing model of interaction, which allows a user to view all applications as data that can be edited. An application interacts with a user by submitting variables (of arbitrary types) to a dialogue manager , which displays their presentations to the user and offers type-directed editing of these presentations. Applications and dialogue managers communicate through a protocol that allows a presentation to be kept consistent with the variable it displays. A particular implementation of the approach, called Dost, has been constructed for the Xerox development environment and the Mesa programming language. Dost is used as a concrete example to describe the editing model, the primitives to support it, and our preliminary experience with these primitives. The approach is compared with related work, its shortcomings are discussed, and suggestions for future work are made.

The use of a special-purpose coprocessor for supporting message passing is proposed. An actual message-based operating system is partitioned into computation and communication parts, executing, respectively, on a host and a message coprocessor which interact through shared queues. Its performance is measured on a multiprocessor. Hardware support in the form of a special-purpose smart bus and smart shared memory is designed. The benefits of these components are demonstrated through analytical modeling using generalized timed Petri nets. The analysis shows good agreement with experimental results and indicates that substantial benefits may be obtained when the software is partitioned between host and the message coprocessor and when a small amount of special-purpose hardware is added.>

In recent years there has been increasing interest in message-based operating systems, particularly in distributed environments. Such systems consist of a small message-passing kernel supporting a collection of system server processes that provide such services as resource management, file service, and global communications. For such an architecture to be practical, it is essential that basic messages be fast, since they often replace what would be a simple procedure call or “kernel call” in a more traditional system. Careful study of several operating systems shows that the limiting factor, especially for small messages, is typically not network bandwidth but processing overhead. Therefore, we propose using a special-purpose coprocessor to support message passing. Our research has two parts: First, we partitioned an actual message-based operating system into communication and computation parts interacting through shared queues and measured its performance on a multiprocessor. Second, we designed hardware support in the form of a special-purpose smart bus and smart shared memory and demonstrated the benefits of these components through analytical modeling using Generalized Timed Petri Nets. Our analysis shows good agreement with the experimental results and indicates that substantial benefits may be obtained from both the partitioning of the software and the addition of a small amount of special-purpose hardware.

This paper presents an overview of the hardware and software components of the Crystal multicomputer project. The goal of the Crystal project is to design and implement a vehicle that serves a variety of research projects involving distributed computation. Crystal can be used simultaneously by multiple research projects by partitioning the available processors according to the requirements of each project. Users can employ the Crystal multicomputer in several ways. Projects such as operating systems and database machines that need direct control of processor resources (clock, memory management, communication devices) can be implemented using a reliable communication service (the "nugget" that resides on each node processor. Projects that prefer a higher-level interface can be implemented using the Charlotte distributed operating system. Finally, users interested in Crystal principally as a cycle server can run UNIX® jobs on node machines using the "remote" unix service. Development, debugging, and execution of projects can take place remotely under the control of any of several UNIX hosts. Acquiring a partition of machines, resetting each machine, and then loading an application onto each machine is performed by invoking a UNIX-resident program (the "nuggetmaster"). Communication with node machines in a partition is facilitated by a virtual terminal and window mechanism. Crystal is fully operational and has been used to support a variety of research projects. To illustrate the flexibility provided by the Crystal environment, four of these projects are described.

The design and implementation study discussed in this paper can be viewed in two ways. On one hand, it represents a contribution to the active area of design of “smart” communications controllers which use increasingly sophisticated processor/memory configurations to improve the performance of interprocessor communication. On the other hand, it represents an application of the minimalist principles of the RISC (Reduced Instruction-Set Computer) architecture [1] to operating systems kernel design.

Unlike other instructions, which compute or test values, unconditional branch instructions do no useful work.Rather, they are artifacts of the translation from a flow graph to the linear form of conventional machine language.Careful ordering of the basic blocks of a program can decrease the number of branches required by allowing a basic block to "fall through" to a successor.It is shown that although the general problem of minimizing the number of branches is NP-complete, an efficient algorithm is possible for "structured" programs--those written without goto statements.More specifically, an algorithm is presented that produces an optimal ordering of the basic blocks of any program that uses only the control structures if-then-else, loop, and exit.The running time of the algorithm is proportional to the length of the program, provided the number of loops exited by any exit statement can be bounded by a constant.

Article Free Access Share on Optimal code for control structures Authors: M. V. S. Ramanath University of Western Ontario, London, Ontario, Canada University of Western Ontario, London, Ontario, CanadaView Profile , Marvin Solomon Universiy of Wisconsin, Madison, Wisconsin Universiy of Wisconsin, Madison, WisconsinView Profile Authors Info & Claims POPL '82: Proceedings of the 9th ACM SIGPLAN-SIGACT symposium on Principles of programming languagesJanuary 1982 Pages 82–94https://doi.org/10.1145/582153.582163Online:25 January 1982Publication History 0citation207DownloadsMetricsTotal Citations0Total Downloads207Last 12 Months5Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

This paper presents a new family of undirected graphs that allows N processors to be connected in a network of diameter 3/2 log2 N + O(1), while only requiring that each processor be connected to three neighbors. The best trivalent graphs previously proposed require a diameter of 2 log2N + O(1).

In this paper we describe a new family of topologies for interconnecting many identical processors to form an MIMD multiprocessor. It extends to arbitrarily many processors while keeping the number of neighbors of any one processor fixed. We show that this family behaves very well with respect to uniformity of bus load, simplicity of routing algorithms, and distance between processors.

Gary Knott has presented algorithms for computing a bljectton between the set of binary trees on n nodes and an mmal segment of the posmve integers Rotem and Varol presented a more complicated algorithm that computes a different bljectmn, clmmmg that thetr algorithm is more efficient and has advantages ff a sequence of several consecutive trees is reqmred A modlficatmn of Knott's algorithm that ts simpler than Knott's and as effioent as Rotem and Varol's is presented Also given is a new hnear-time algorithm for transforming a tree mto ~ts successor m the natural ordering of binary trees

In this paper, we describe four families of topologies for interconnecting many identical processors into a computer network. Each family extends to arbitrarily many processors while keeping the number of neighbors of any one processor fixed. These families are investigated with respect to bus load, routing algorithms, and the relation between the average interprocessor distance and the size of the network.

Roscoe is an operating system implemented at the University of Wisconsin that allows a network of microcomputers to cooperate to provide a general-purpose computing facility. After presenting an overview of the structure of Roscoe, this paper reports on experience with Roscoe and presents several problems currently being investigated by the Roscoe project.

It has long been known that recursively defined types in a highly typed language such as Algol 68 or Pascal may be tested for structural equivalence by the same algorithm that compares finite automata [5,11]. Several authors (for example, [3,8,9,16]) have proposed that classes of types be simultaneously defined by the use of parameterized type definitions, such asType list(x) = record val:x; next:↑list(x) end .This paper shows that unless the use of such parameterized definitions is restricted, new (unparameterized) types may be defined which more closely resemble deterministic context-free languages. In fact, the equivalence problem for such types becomes as hard as the (currently unsolved) deterministic pushdown automaton equivalence problem. Several restrictions on type definitions are considered which allow known equivalence algorithms to be applied.

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