Now showing items 1-20 of 42

    • Adapting Protocols to Massively Interconnected Systems 

      Kafura, Dennis G.; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1991-05-01), TR-91-27
      This paper describes ongoing research focused on two critical problems posed by the interconnection of a massive number of computer systems. The interconnection may be achieved through wide area or local area networks. The ...
    • Analysis of Bottlenecks in International Internet Links 

      Ahsan Habib, Md; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1998-12-01), TR-98-24
      We report on preliminary results of analysis into the sources of congestion in international Internet routes from the United States to several countries: Brazil and South Africa. Using the pathchar and traceroute tools, ...
    • Approximate Time-Parallel Simulation of Queueing Systems with Losses 

      Wang, Jain J.; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-08
      This paper presents a guideline of a partial state matching approach for time-parallel simulation. Two algorithms using this approach to simulate FCFS G/G/1/K and G/D/1/K queues in which arriving customers that find the ...
    • Beyond Software Performance Visualization 

      Abrams, Marc; Lee, Timothy; Cadiz, Horacio; Ganugapati, Krishna (Department of Computer Science, Virginia Polytechnic Institute & State University, 1994-02-01), TR-94-07
      Performance visualization tools of the last decade have yielded new insights into the new behavior of sequential, parallel, and distributed programs. However, they have three inherent limitations: (1) They only display ...
    • Caching Proxies: Limitations and Potentials 

      Abrams, Marc; Standridge, Charles R.; Abdulla, Ghaleb; Williams, Stephen; Fox, Edward A. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1995-07-01), TR-95-12
      As the number of World-Wide Web users grow, so does the number of connections made to servers. This increases both network load and server load. Caching can reduce both loads by migrating copies of server files closer ...
    • CHITRA94: A Tool to Dynamically Charaterize Ensembles of Traces for Input Data Modeling and Output Analsis 

      Abrams, Marc; Batongbacal, Alan; Ribler, Randy; Vazirani, Devendra (Department of Computer Science, Virginia Polytechnic Institute & State University, 1994-06-01), TR-94-21
      CHITRA94 is the third generation of a comprehensive system to visualize, transform, statistically analyze, and model ensembles of trace data and validate the resultant models. The tool is useful for deriving input data ...
    • Chitra: Visual Analysis of Parallel and Distributed Programs in the Time, Event, and Frequency Domains 

      Abrams, Marc; Doraswamy, Naganand; Mathur, Anup (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-24
      Chitra analyzes a program execution sequence (PES) collected during execution of a program and produces a homogeneous, semi-Markov chain model fitting the PES. The PES represents the evolution of a program state vector in ...
    • Computational Geometric Performance Analysis of Limit Cycles in Timed Transition Systems 

      Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1993-09-01), TR-93-30
      Certain parallel software performance evaluation problems are equivalent to computational geometric problems. Consider a timed transition system representing a parallel program: a set of variables, a set of states, an ...
    • The Cost of Terminating Optimistic Parallel Discrete-Event Simulations 

      Sanjeevan, Vasant; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-25
      In a previous paper, we proposed seven algorithms for mechanically adding an arbitrary termination condition to a conservative-synchronous, non-terminating parallel simulation. Informal arguments about the performance of ...
    • Design Issues in General Purpose, Parallel Simulation Languages 

      Abrams, Marc; Lomow, Greg (Department of Computer Science, Virginia Polytechnic Institute & State University, 1989), TR-89-38
      This paper addresses the topic of designing general purpose, parallel simulation languages. We discuss how parallel simulation languages differ from general purpose programming languages. Our thesis is that the issues ...
    • Determining Initial States for Time-Parallel Simulations 

      Wang, Jain J.; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-53
      In this paper, we propose a time-parallel simulation method which uses a pre-simulation to identify recurrent states. Also, an approximation technique is suggested for approximate Markovian modeling for queueing networks ...
    • The Effectiveness of Cache Coherence Implemented on the Web 

      Doswell, Felicia; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 2000-08-01), TR-00-02
      The popularity of the World Wide Web (Web) has generated so much network traffic that it has increased concerns as to how the Internet will scale to meet future demand. The increased population of users and the large size ...
    • Formally Reasoning About and Automatically Generating Sequential and Parallel Simulations 

      Abrams, Marc; Page, Ernest H. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-55
      This paper proposes a methodology to automate the construction of simulation programs within the context of a simulation support environment. The methodology starts with a simulation model specification in the form of a ...
    • Geometric Performance Analysis of Mutual Exclusion: The Model 

      Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1990), TR-90-58
      This paper is motivated by the need to better understand parallel program run-time behavior. The paper first formally describes a general model of program execution based on Djkstra's progress graphs. The paper then ...
    • Geometric Performance Analysis of Mutual Exclusion: The Model Solution 

      Abrams, Marc; Agrawala, Ashok (Department of Computer Science, Virginia Polytechnic Institute & State University, 1990), TR-90-59
      This paper presents an analytic solution to progress graphs used for performance analysis. It derives the exact sequence of blocking and running times experienced by two processes sharing mutually exclusive, reusable ...
    • Geometric Performance Analysis of Semaphore Programs 

      Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1993-08-01), TR-93-29
      A key problem in designing parallel programs that achieve a desired performance goal is the ability to analyze exactly program performance, given a specification of the process syncronization structure and the execution ...
    • The Impact of Lookahead on Conservative Simulation 

      Wang, Jain J.; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1995-02-01), TR-95-03
      This paper studies the impact on the performance of conservative simulation for both open and closed models. For open models, we derive an upper bound on the performance improvement due to the lookahead. We show that the ...
    • Implementing a Global Termination Condition and Collecting Output Measures in Parallel Simulation 

      Abrams, Marc; Richardson, Debra S. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1990), TR-90-54
      This paper investigates how to implement arbitrary global termination conditions and collect statistics in a parallel simulation. The problem is first discussed using Chandy and Sherman's space-time framework. Then ...
    • Implications of Using the Event Scheduling World View for Parallel Simulation 

      Richardson, Debra S.; Abrams, Marc (Department of Computer Science, Virginia Polytechnic Institute & State University, 1990), TR-90-44
      Use of a particular world view, or conceptual framework, makes the programming of many simulations easier. Parallel simulation implementations generally have not been based on a particular world view. An open question ...
    • An Introduction to Visualizing Program Execution Dynamics with Chitra 

      Abrams, Marc; Doraswamy, Naganand (Department of Computer Science, Virginia Polytechnic Institute & State University, 1992), TR-92-23
      We describe a tool called Chitra, which serves two purposes. First, Chitra visualizes program execution sequences (PES's) collected by monitoring parallel and distributed program execution in the time, event, and frequency ...