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This research explores the challenges of analyzing resource-constrained distributed systems using simulation-guided model checking. It proposes a model-based approach for the design and analysis of embedded systems, with a focus on domain-specific modeling and simulation-guided model checking. The research also introduces the DREAM framework for architectural exploration and provides an open-source tool for automatic timed automata model generation.
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Real-time Analysis of Resource-Constrained Distributed Systems by Simulation-Guided Model Checking Gabor Madl (gabe@ics.uci.edu), Ph.D. Candidate, UC Irvine Advisor: Nikil Dutt (dutt@ics.uci.edu) Chancellor’s Professor, UC Irvine RTSS 2007 Ph.D. Forum
Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Analysis of Embedded Systems • Distributed real-time embedded (DRE) systems are often reactive and event-driven • Better latency than in synchronous/time-triggered systems • Easier to implement, no need for global synchronization • Computations are driven by events – complex model • Asynchrony, concurrency, race conditions • Hard to predict all behaviors • Have to satisfy multiple constraints • Real-time, energy consumption, reliability, fault-tolerance • Functional verification, real-time analysis, performance estimation are key challenges • Task execution times, delays, parallelism, throughput
Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Continuous-time Analysis • In DRE systems classic scheduling methods may result in scheduling anomalies • Hard to analyze real-time properties • In practical event-driven systems, exhaustive analysis is often infeasible due to the state space explosion problem • We need methods that can capture continuous-time execution intervals, and event-based triggering
Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Need to Combine Analysis Methods • Static analysis methods • Often too abstract, resulting in conservative/inaccurate results • Cannot capture dynamic effects • Simulations • Can show the presence of an error, never its absence • Ad-hoc, hard to measure coverage • Limited design space exploration • Model checking • State space explosion problem • No partial results • Time consuming and costly • Each method has its advantage and disadvantage
Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Model-based Design & Analysis • We propose a model-based approach for the design & analysis of embedded systems • The design flow is driven by the DSM, a high-level specification that captures key properties • The DSM is mapped to a formal executable model to allow verification and evaluation • Formal models drive functional verification • We propose the combination of simulations and formal methods for the evaluation of designs
Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Domain-Specific Modeling • We utilize meta-modeling to specify modeling languages • The modeling language is used for the specification and early exploration of design alternatives • Designers work on models that are based on their domains of expertise, they do not have to become experts in formal methods as well • We focus on two domains • DRE systems • Multi-processor System-on-Chip (MPSoC) designs
Challenges Model-based Analysis Simulation-guided Model CheckingDREAM Framework Simulation-Guided Model Checking • Parameters for components obtained by simulations • Utilize model checking and discrete event simulations on symbolic models to increase coverage
Model checking for the functional verification of protocols Simulation-guided performance estimation of MPSoCs Use results as parameters for higher-level models Compose methods to improve accuracy, scalability Better understanding of interactions between components Challenges Model-based Analysis Simulation-guided Model CheckingDREAM Framework Architectural Exploration
ALDERIS model GME tool Verimag IF model checker ALDERIS model XML representation UPPAAL model checker Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework DREAM Analysis Framework Open-source DREAM Tool Automatic timed automata model generation for the UPPAAL and Verimag IF tools Simulation-guided model checking Performance Estimation using DES Random testing Schedulability optimizations http://dre.sourceforge.net
Questions? Links to relevant work: http://dre.sourceforge.net http://alderis.ics.uci.edu http://www.ics.uci.edu/~gabe RTSS 2007 Ph.D. Forum