2014
Authors
Barros, A; Pinho, LM;
Publication
Architecture of Computing Systems - ARCS 2014 - 27th International Conference, Lübeck, Germany, February 25-28, 2014. Proceedings
Abstract
Recent embedded processor architectures containing multiple heterogeneous cores and non-coherent caches, bring renewed attention to the use of Software Transactional Memory (STM) as a building block for developing parallel applications. STM promises to ease concurrent and parallel software development, but relies on the possibility of abort conflicting transactions to maintain data consistency, which affects the execution time of tasks carrying transactions. Thus, execution time overheads resulting from aborts must be limited, otherwise the timing behaviour of the task set will not be predictable. In this paper we formalise a FIFO-based algorithm to order the sequence of commits of concurrent transactions. Furthermore, we propose and evaluate two non-preemptive scheduling strategies, in order to avoid transaction starvation. © 2014 Springer International Publishing Switzerland.
2025
Authors
Carvalho, T; Müller, T; Reiter, S; Pinho, LM; Oliveira, A;
Publication
International Conference on Model-Driven Engineering and Software Development
Abstract
The Internet of Things (IoT) enables everyday objects to connect and communicate remotely, transforming areas such as smart homes and industrial automation. IoT systems can be standalone or interconnected in a System of Systems, where multiple devices work together towards a common goal. A key application is Energy Monitoring Systems (EMS), which track energy use within communities, using energy production and consumption. Designing this type of IoT systems remains complex and requires careful consideration of heterogeneous devices, their limitations, software, communication protocols, data management, and security. This paper presents a design approach for EMS communities, with a focus on house-level IoT systems. We introduce a model-driven development methodology, a holistic and flexible framework for designing IoT systems across the development and operations lifecycle. Especially, the concept of projectors enables an easy shift between domain assets and provide automation support. The approach is validated with a real-life use case, for which an analysis phase was developed, showing the benefits of using our approach for managing EMS and the automation of the analysis configuration. © 2025 by SCITEPRESS - Science and Technology Publications, Lda.
2025
Authors
Paschoaletto, A; Sousa, P; Pinho, LM; Carvalho, T;
Publication
2025 28th International Symposium on Real-Time Distributed Computing (ISORC)
Abstract
The Constant Bandwidth Server (CBS) is a mechanism used in real-time systems to enable aperiodic soft realtime tasks with unknown execution parameters to run under a dynamic scheduling policy such as Earliest Deadline First (EDF), while still ensuring schedulability by using a bandwidth reservation strategy. This paper proposes an approach to extend the Zephyr open-source real-time operating system, currently maintained by the Linux Foundation, to support aperiodic tasks with CBS. The paper provides the proposed architecture and the design and implementation of the CBS mechanisms in the operating system, which are then evaluated in two test cases in an embedded platform. © 2025 Elsevier B.V., All rights reserved.
2024
Authors
Pinho, LM;
Publication
2024 IEEE 14TH INTERNATIONAL SYMPOSIUM ON INDUSTRIAL EMBEDDED SYSTEMS, SIES
Abstract
Developing real-time systems applications requires programming paradigms that can handle the specification of concurrent activities and timing constraints, and controlling execution on a particular platform. The increasing need for high-performance, and the use of fine-grained parallel execution, makes this an even more challenging task. This paper explores the state-of-the-art and challenges in real-time parallel application development, focusing on two research directions: one from the high- performance domain (using OpenMP) and another from the real-time and critical systems field (based on Ada). The paper reviews the features of each approach and highlights remaining open issues.
2015
Authors
Martínez, RG; Nelissen, G; Ferreira, LL; Pinho, LM;
Publication
Architecture of Computing Systems - ARCS 2015 - 28th International Conference, Porto, Portugal, March 24-27, 2015, Proceedings
Abstract
Distributed real-time systems such as automotive applications are becoming larger and more complex, thus,
requiring the use of more powerful hardware and software architectures. Furthermore, those distributed
applications commonly have stringent real-time constraints. This implies that such applications would gain in
flexibility if they were parallelized and distributed over the system. In this paper, we consider the problem of
allocating fixed-priority fork-join Parallel/Distributed real-time tasks onto distributed multi-core nodes connected
through a Flexible Time Triggered Switched Ethernet network. We analyze the system requirements and present a
set of formulations based on a constraint programming approach. Constraint programming allows us to express
the relations between variables in the form of constraints. Our approach is guaranteed to find a feasible solution,
if one exists, in contrast to other approaches based on heuristics. Furthermore, approaches based on constraint
programming have shown to obtain solutions for these type of formulations in reasonable time.
2013
Authors
Pinho L.; Michell S.; Moore B.;
Publication
Ada User Journal
Abstract
Experts provided information about parallel and multicore systems in papers submitted and discussed at a workshop. Discussion followed about the wisdom of giving any directive further than with parallel for the programmers to control the details of how parallelism was configured, executed, and potentially mapped in the runtime. The counter argument was raised that in real-time systems there was a need for the programmer to specify such control to directly specify the behavior, which was required for behavior analysis and timing behavior analysis. Questions were raised about the memory model of the proposal, and it was decided that the general model was that which supported a shared memory system, with cache coherency and uniform access to memory= within a single partition.
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