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Title:Next-generation safety-critical systems on multi-core platforms
Author(s):Mancuso, Renato
Director of Research:Caccamo, Marco
Doctoral Committee Chair(s):Caccamo, Marco
Doctoral Committee Member(s):Sha, Lui; Abdelzaher, Tarek; Brandenburg, Björn
Department / Program:Computer Science
Discipline:Computer Science
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Real-time systems
Multi-core systems
Commercial-off-the-shelf (COTS)
Single-core equivalence
Single-core equivalent
Hardware resource management
Operating system (OS)
Real-time operating system (RTOS)
Worst case execution time (WCET)
Schedulability analysis
Multi-core real-time operating system (RTOS)
Cyber-physical systems (CPS)
Colored lockdown
Kernel verification
Scratchpad-centric operating system (OS)
Scratchpad memories operating system (SPM-OS)
Scratchpad scheduling
Direct memory access (DMA) scheduling
Flow-shop task
Flow-shop scheduling
Hardware scheduler
Field-programmable gate array (FPGA) scheduler
Real-time Linux
Smart manufacturing
Real-time networking
Embedded systems
Multi-core avionics
Multi-core automotive
Self-driving cars
Multi-core safety-critical
Reconfigurable computing
Internet of things
Real-time cloud computing
Provably safe cyber-physical systems (CPS)
Multi-core scheduling
Performance isolation
Real-time resource management
Real-time cache
Real-time dynamic random access memory (DRAM)
Inter-core interference
Interference channels
Federal Aviation Administration (FAA)
Minimal multicore avionics certification guidance
Multi-core automotive open system architecture (AUTOSAR)
Resource partitioning
Multi-core resource partitioning
Predictable execution model (PREM)
Multi-core predictable execution model (PREM)
Abstract:Multi-core platforms represent the answer of the industry to the increasing demand for computational capabilities. In fact, multi-core platforms can deliver large computational power together with minimum costs, compact size, weight and power usage. Multi-core architectures however are shaking the very foundation of modern real-time computing theory, i.e. the assumption that worst case execution time (WCET) can be calculated on individual tasks to compute the schedulability of the complete system when tasks are running together. This fundamental assumption has been broadly accepted by classic scheduling theory for the past three decades; unfortunately, it is not even true in an approximate sense in a modern multi-core chip, and this leads to a lack of composability. Shared hardware resources like caches, main memory, and I/O buses are all sources of unpredictable timing behavior and temporal dependencies among real-time tasks running in parallel. As a result, certifying systems deployed using multi-core platforms is significantly more challenging compared to single-core implementations. In this work, we tackle the challenge of restoring the constant WCET assumption for real-time tasks deployed on multi-core systems. While predictability and performance determinism are of paramount importance in safety-critical applications, cost containment and time-to-market are dominant factors for the large-scale adoption of novel technologies. Hence, our work proposes solutions that can be adopted with commercially available components, also known as commercial-off-the-shelf (COTS) components. In order to achieve deterministic performance on COTS multi-core platforms, we propose software-level techniques to enforce usage control over shared hardware resources. We also demonstrate that when proper enforcement is performed, real-time analysis can be carried out efficiently. We focus our attention on two main multi-core architectural paradigms: cache-based and scratchpad-based platforms. On multi-core cache-based architectures, we design, implement and analyse a set of OS-level techniques that enforce hardware resource partitioning. In this context, we set two main goals. Our first objective is to achieve strong inter-core performance isolation in spite of inherent hardware resource sharing. On the other hand, our techniques are designed to remain transparent from an application perspective. This requirement allows for minimum re-engineering being required to port legacy single-core systems on multi-core platforms partitioned with the proposed techniques. On scratchpad-based platforms, we follow a different approach. In fact, we propose a redesign of the OS-level scheduling strategies. The goal is to include scratchpad space scheduling, as well as shared memory bus access, together with traditional processor time scheduling. The resulting resource co-scheduling strategy introduces a set of new challenges compared to processor-only scheduling. Nonetheless, it allows to significantly mitigate the problem of inter-core performance interference, as we describe in our evaluations.
Issue Date:2017-04-19
Rights Information:Copyright 2017 Renato Mancuso
Date Available in IDEALS:2017-08-10
Date Deposited:2017-05

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