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 November 11, 2018

Analysis of Embedded Systems 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 November 11, 2018

Continuous-time Analysis 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 November 11, 2018

Need to Combine Analysis Methods 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 November 11, 2018

Model-based Design & Analysis 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 November 11, 2018

Domain-Specific Modeling 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 November 11, 2018

Simulation-Guided Model Checking Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Simulation-Guided Model Checking Parameters for components obtained by simulations Utilize model checking and discrete event simulations on symbolic models to increase coverage November 11, 2018

Architectural Exploration Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework Architectural Exploration 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 November 11, 2018

DREAM Analysis Framework Challenges Model-based Analysis Simulation-guided Model Checking DREAM Framework DREAM Analysis Framework ALDERIS model GME tool 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 Verimag IF model checker ALDERIS model XML representation UPPAAL model checker http://dre.sourceforge.net November 11, 2018

Links to relevant work: 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 November 11, 2018