Collaborative Research: CSR-EHS: Modeling and Exploiting Cross-Layer Timing in Distributed Embedded Systems

嵌入式和混合系统（EHS）应用程序是高度网络化的系统，具有端到端的需求，涉及分布式环境中多层（应用程序、中间件、网络、操作系统、体系结构）之间的交互。在这些分布式跨层系统中，理解时间的整体方法至关重要，因为：EHS应用程序经常面临端到端的硬实时或软实时需求；跨层系统的定时粒度可以以数量级变化，这对可以解释这些变化的定时分析提出了挑战；了解不同级别的时序参数可以极大地提高EHS应用程序的实用性和性能，这些应用程序通常在CPU、内存、网络带宽和设备能量有限的受限环境中执行。该项目探索了高度分布式嵌入式系统中跨层计时的概念，使用正式方法和实验系统的混合，将嵌入式计算、分布式系统和正式方法方面的专业知识汇集在一起。该项目将(1)开发新的形式化方法，用于对分布式嵌入式系统中的跨层定时属性进行建模和推理，以及(2)设计机制/策略，以经济有效地解决基于跨层定时分析的QoS/性能权衡。结果将在移动多媒体应用程序的环境中进行验证和测试，这些应用程序在高度动态的环境中执行，并为权衡分析和执行提供了有趣的机会。对时间问题的全面解决方案将支持分布式嵌入式应用程序的更广泛的适用性和采用，并为跨多个抽象级别统一处理其他非功能约束奠定基础

Embedded and hybrid system (EHS) applications are highly networked systems with end-to-end requirements that involve interactions among multiple layers (application, middleware, network, OS, architecture) in a distributed environment. A holistic approach to understanding timing in these distributed cross layer systems is critical since:EHS applications often face end-to-end hard or soft real-time needs; timing granularities for cross-layer systems can vary by orders of magnitude posing a challenge for timing analysis that can account for these variations; and knowledge of timing parameters at the different levels can dramatically improve the utility and performance of EHS applications that often execute in constrained environments where CPU, memory, network bandwidth and device energy is limited.This project explores the notion of cross-layer timing in highly distributed embedded systems using a blend of formal methods and experimental systems, bringing together researchers with expertise in embedded computing, distributed systems and formal methods. The project will (1) develop novel formal methodologies for modeling and reasoning about cross-layer timing properties in distributed embedded systems, and (2) design mechanisms/policies that will cost-effectively address the QoS/performance tradeoffs based on the cross-layer timing analyses. The results will be validated and tested in the context of mobile multimedia applications that execute in highly dynamic environments and present interesting opportunities for tradeoff analysis and enforcement. A comprehensive solution to the timing issue will enable the wider applicability and adoption of distributed embedded applications and lay the groundwork for the unified treatment of other non-functional constraints across multiple abstraction levels