Casey Reardon

Ethernet Adaptive Link Rate (ALR): Analysis of a MAC Handshake Protocol

In this paper, a handshake protocol at the medium access control (MAC) layer is proposed and analyzed for dynamically changing the link rate in the network interface card (NIC), adapting to network utilization, and thus decreasing average power consumption. Simulation results show that this protocol can be used to change link rate in Ethernet network devices without causing user-perceivable delays

Power-Proxying on the NIC: A Case Study with the Gnutella File-Sharing Protocol

Edge devices such as desktop and laptop computers constitute a majority of the devices connected to the Internet today. Peer-to-peer (P2P) file-sharing applications generally require edge devices to maintain network presence whenever possible to enhance the robustness of the file-sharing network, which in turn can lead to considerable wastage of energy. We show that energy can be saved by permitting edge devices to enter into standby state and still maintain network connectivity by proxying protocols in the network interface card (NIC)

A Simulation Framework for Rapid Analysis of Reconfigurable Computing Systems

Reconfigurable computing (RC) is rapidly emerging as a promising technology for the future of high-performance and embedded computing, enabling systems with the computational density and power of custom-logic hardware and the versatility of software-driven hardware in an optimal mix. Novel methods for rapid virtual prototyping, performance prediction, and evaluation are of critical importance in the engineering of complex reconfigurable systems and applications. These techniques can yield insightful tradeoff analyses while saving valuable time and resources for researchers and engineers alike. The research described herein provides a methodology for mapping arbitrary applications to targeted reconfigurable platforms in a simulation environment called RCSE. By splitting the process into two domains, the application and simulation domains, characterization of each element can occur independently and in parallel, leading to fast and accurate performance prediction results for large and complex systems. This article presents the design of a novel framework for system-level simulative performance prediction of RC systems and applications. The article also presents a set of case studies analyzing two applications, Hyperspectral Imaging (HSI) and Molecular Dynamics (MD), across three disparate RC platforms within the simulation framework. The validation results using each of these applications and systems show that our framework can quickly obtain performance prediction results with reasonable accuracy on a variety of platforms. Finally, a set of simulative case studies are presented to illustrate the various capabilities of the framework to quickly obtain a wide range of performance prediction results and power consumption estimates.

Strategic Challenges for Application Development Productivity in Reconfigurable Computing

Performance and versatility requirements arising from escalating fabrication costs and design complexities are making reconfigurable computing technologies increasingly advantageous on the roadmap towards many-core technologies. This reformation in device architectures is necessitating a critical reformation in application design methods to bridge the widening semantic gap between design productivity and execution efficiency. This paper explores the strategic challenges in FPGA design methodologies and evaluates potential solutions and their impact on future DoD applications and users. A new research initiative, strategic infrastructure for reconfigurable computing applications (SIRCA), has also been proposed as a potential new DARPA program to address the FPGA productivity problem.

Comparative Simulative Analysis of WDM Lans for Avionics Platforms

With their almost unlimited potential for performance and their decreasing costs, advanced optical components and networks are now being seriously considered for deployment in emerging avionics systems. Towards the goal of developing an advanced avionics network that features wave-division multiplexing (WDM) for performance that is highly scalable, dependable, protocol-independent, and versatile, many disparate architecture strategies need to be evaluated. Due to the high cost of testbed prototyping and integration with existing systems, a simulative approach is used in this study to analyze and compare candidate WDM LAN architectures at a high level. Using discrete-event simulation models developed at the University of Florida, several contrasting approaches are examined for constructing an optical network architecture supportive of future avionics requirements. Each architecture is evaluated in terms of two application scenarios. The results from the simulation experiments enable a high-level comparison of competing architectures and provide insight for aerospace network researchers and designers

RCML: An Environment for Estimation Modeling of Reconfigurable Computing Systems

Reconfigurable computing (RC) is emerging as a promising area for embedded computing, in which complex systems must balance performance, flexibility, cost, and power. The difficulty associated with RC development suggests improved strategic planning and analysis techniques can save significant development time and effort. This article presents a new abstract modeling language and environment, the RC Modeling Language (RCML), to facilitate efficient design space exploration of RC systems at the estimation modeling level, that is, before building a functional implementation. Two integrated analysis tools and case studies, one analytical and one simulative, are presented illustrating relatively accurate automated analysis of systems modeled in RCML.

Classification of Application Development for FPGA-Based Systems

Field-programmable gate arrays (FPGAs) have been used to accelerate DoD-related applications with promising performance. However, current development tools require significant hardware knowledge and are not amenable to the increasing complexity of FPGA-based systems. The application requirements are expected to change dramatically for future use cases, and require a well defined development methodology. This paper presents the results obtained after conducting an extensive survey and study about current FPGA tools. A classification for DoD use cases and FPGA tools is provided. This classification provides the current status of the available tools and identifies current tool limitations for DoD use cases.

An End-to-End Tool Flow for FPGA-Accelerated Scientific Computing

As part of their ongoing work with the National Science Foundation (NSF) Center for High-Performance Reconfigurable Computing (CHREC), the authors are developing a complete tool chain for FPGA-based acceleration of scientific computing, from early-stage assessment of applications down to rapid routing. This article provides an overview of this tool chain.

Wavelength Allocation Strategies in Optically Switched Networks for Avionics

In this paper, an architecture for an optically-switched avionics network is presented. The performance of this architecture was analyzed using simulative experiments for two wavelength allocation strategies. Additionally, the effects of varying the timeslot period and maximum number of consecutively allotted timeslots were analyzed. Results showed slightly lower packet latencies with a fixed-destination wavelength protocol. Larger timeslot periods, up to 1,000 ns, also improved performance, although further increases would not be beneficial. The optimal parameters for any platform will always depend upon the nature of the network traffic. Our modeling tools and approach allow us to evaluate such design decisions for a wide range of network scenarios

Virtual prototyping of WDM avionics networks

This paper introduces a library for simulation modeling of optical communication networks, focusing on performance analysis for advanced aerospace platforms, and features a case study of virtual prototyping for comparison of several system design strategies.