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2009, International Journal …
AI
OveRSoC is a framework designed to effectively explore the design space of Real-Time Operating Systems (RTOS) for Reconfigurable System on Chip (RSoC) platforms. It addresses the complexity associated with heterogeneous architectures by providing a high-level model that supports efficient management of reconfigurable resources and ensures real-time constraints are met. The framework emphasizes exploration, incremental refinement, separation of concerns, and reusability to streamline the design process in embedded applications.
2005
Reconfigurable resources are more and more envisaged inside System-on-Chip designs for facing with embedded computing power constraints. Moreover, a high level of flexibility of such platforms is required and can only be achieved with embedded software and real-time operating systems (RTOS) services. Unfortunately, this leads to very complex and heterogeneous platforms that cannot be easily validated nor modeled with classical design tools. This paper presents the objective and the proposed methodology of the OVERSOC project. This project aims at developing a global methodology and the associated tools for a design space exploration of interactions between embedded real-time operating systems and reconfigurable SoC platforms.
System level modeling has been adopted for few years as a way to face the growing design complexity of embedded systems. In this systems the control of embedded applications is more and more often devoted to a Real-Time Operating System (RTOS). This RTOS can either be deployed in software or hardware, partially or completely, depending on the non-functional constraints of the global system. Consequently, these new design decisions concerning the implementation of the control must be taken early in the design flow for software and hardware parts.
Proceedings of the International Forum on …
The design process of embedded systems moves currently towards higher levels of abstraction. As a consequence, a need arises for an early and realistic assessment of system level design decisions. In order to provide the early access, an automatic generation of its simulation models is advocated. While Verilog and VHDL are being extended in order to improve their system-level capabilities, SystemC community is intensively extending SystemC to software modeling features. In this sense, SystemC support for a realistic assessment of embedded system in the process of develop-validate-and-test its software is advocated. This step is done before any decisions with respect to processor and operating system has been finalized, as well as before an executable platform model and prototype board becomes available. Moreover, while execution properties of embedded software processes, which more and more dominate the functionality of embedded systems, can considerably vary both due to processor pipeline and cache structures, the chosen scheduling policy influences distinctly the execution properties. Unfortunately, the current version of SystemC is still lack of that software modeling support. Therefore, the modeling capability of SystemC is being extended in this paper by generic real-time operating system services providing more realistic software modeling features. The features cover also modelling dynamic process creation, process control, pre-emption, process prioritization, inter-process communication, and synchronization, as well as static and dynamic scheduling. Design alternatives can thus be easily validated and different scheduling policies can be explored. The figures of merit of the proposed approach are demonstrated by means of the embedded information processing of a mobile robot.
Multiprocessed System-on-Chip (MPSoCs) have become a recurrent implementation alternative to modern embedded systems and, lately, have counted on resources previously available only on general purpose machines. In this context, it is possible to highlight that many techniques formerly adopted in general-purpose computers have been studied and adapted to the embedded reality. Thus, embedded communication infrastructures such as buses and networks-on-Chip (NoCs) are based on general-purpose solutions and are widely accepted for embedded systems. Also, embedded systems make use of Operating Systems (OS), as they provide standard interfaces to access hardware resources, including the communication facilities. However, although the underlying communication infrastructure can differ in order to improve a given metric, such as performance, power or area, it is desirable that the software layer remains the same, especially in terms of the application's and OS's code improving the overall software quality. Still, certain OS parameters can directly influence on the overall system performance. This paper presents a highly configurable Real Time OS (RTOS) that implements a communication protocol to provide a transparent communication interface for both bus-and NoC-based MPSoCs' applications.
IEEE International Conference on Computer-Aided Design, 1998
We survey the state-of-the-art in real-time operating systems (RTOSs) from the system synthesis point of view. RTOSs have a very long research history which provides important theoretical results and useful industrial implementations. Convergence of applications, technology, and market trends of embedded systems implies a strong need for new generation of RTOS. Therefore, new system synthesis problem areas, notably hardware/software co-design and synthesis for systems-on-silicon (SOS), are opening up new avenues for RTOS research and development. This paper starts with a survey of classical academic and industrial RTOS work and continues with a survey of recent results related to co-design and design systems-on-silicon. We conclude by outlining future directions for the SOS RTOS.
OpenComRTOS is one of the few Real-Time Operating Systems for embedded systems that was developed using formal modelling techniques. The goal was to obtain a proven dependable component with a clean ar-chitecture that delivers high performance on a wide variety of networked embedded systems, ranging from a single processor to distributed systems. The result is a scalable reliable communication system with real-time capabilities. Besides, a rigorous formal verification of the kernel algorithms led to an architecture which has several properties that enhance safety and real-time properties of the RTOS. The code size in particular is very small, typically 10 times less than a typical equivalent single processor RTOS. The small code size allows a much better use of the on-chip memory resources, which increases the speed of execution due to the reduction of wait states caused by the use of external memory. To this point we ported OpenComRTOS to the MicroBlaze processor from Xilinx, the L...
2014 International Conference on Electronic Systems, Signal Processing and Computing Technologies, 2014
The paper discusses the literature survey of RTOS (Real Time Operating Systems) and its contributions to the embedded world. RTOS is defined as a system in which the correctness of the system does not depend only on the logical results of computation but also on the time at which the results are produced. It has to perform critical tasks on priority basis keeping the context switching time minimum. It is often associated with few misconceptions & we have tried to throw some light on it. Since last 20 years, RTOS is undergoing continuous evolution and has resulted into development of many commercial RTOS products. We have selected few commercial RTOS of different categories of real-time applications and have discussed its real-time features. A comparison of the commercial RTOSs' is presented. We conclude by discussing the results of the survey and comparing the RTOS based on performance parameters.
The development of Multi‐Processors Systems on Chip (MPSoC) has increased recently due to their high processing speed and low‐power consumption. Software implementation of these systems rely on parallel computing, a different programming paradigm which has not been fully adopted by most of the developers. Real‐Time Operating Systems (RTOS) is one of the most important pieces in an embedded system. Unfortunately, some RTOSs have been mostly released for single processor embedded systems and there are just a few research‐purposes multiprocessor operating systems. This paper explores some alternatives reported in the literature to the implementation of MPSoC operating systems. One of the most promising commercial MPSoC RTOS called FreeRTOS xcore is introduced and described. The characteristics of this MPSoC RTOS are contrasted with those of some other available RTOSs, concluding that FreeRTOS xcore is a suitable operating system for mid‐range multiprocessor systems, where easy and fast implementation is a crucial constraint.
Design Automation for Embedded Systems, 2007
One of the challenges of designing a heterogeneous multiprocessor SoC is to find the right partitioning of the application for the target platform architecture. The right partitioning is dependent on the characteristics of the processors and the network connecting them as well as the application. We present an abstract system-level modelling and simulation framework (ARTS) which allows for cross-layer modelling and analysis covering the application layer, middleware layer, and hardware layer. ARTS allows MPSoC designers to explore and analyze the network performance under different traffic and load conditions, consequences of different task mappings to processors (software or hardware) including memory and power usage, and effects of RTOS selection, including scheduling, synchronization and resource allocation policies. We present the application and platform models of ARTS as well as their implementation in SystemC. We present the usage of the ARTS framework as seen from platform developers' point of view, where new components may be created and integrated into the framework, and from application designers' point of view, where existing components are used to explore possible implementations. The latter is illustrated through a case study of a real-time, smart phone application consisting of 5 applications with a total of 114 tasks mapped onto different platforms. Finally, we discuss the simulation performance of the ARTS framework in relation to scalability.
ACM Transactions on Reconfigurable Technology and Systems, 2015
This article presents a new solution for easing the development of reconfigurable applications using Field-Programable Gate Arrays (FPGAs). Namely, our Reliable Reconfigurable Real-Time Operating System (R3TOS) provides OS-like support for partially reconfigurable FPGAs. Unlike related works, R3TOS is founded on the basis of resource reusability and computation ephemerality. It makes intensive use of reconfiguration at very fine FPGA granularity, keeping the logic resources used only while performing computation and releasing them as soon as it is completed. To achieve this goal, R3TOS goes beyond the traditional approach of using reconfigurable slots with fixed boundaries interconnected by means of a static communication infrastructure. Instead, R3TOS approaches a static route-free system where nearly everything is reconfigurable. The tasks are concatenated to form a computation chain through which partial results naturally flow, and data are exchanged among remotely located tasks ...
Proceedings of the 1998 IEEE/ACM international conference on Computer-aided design - ICCAD '98, 1998
We survey the state-of-the-art in real-time operating systems (RTOSs) from the system synthesis point of view. RTOSs have a very long research history which provides important theoretical results and useful industrial implementations. Convergence of applications, technology, and market trends of embedded systems implies a strong need for new generation of RTOS. Therefore, new system synthesis problem areas, notably hardware/software co-design and synthesis for systems-on-silicon (SOS), are opening up new avenues for RTOS research and development. This paper starts with a survey of classical academic and industrial RTOS work and continues with a survey of recent results related to co-design and design systems-on-silicon. We conclude by outlining future directions for the SOS RTOS.
Proceedings. 2003 International Symposium on System-on-Chip (IEEE Cat. No.03EX748), 2003
In this paper; we present a SystemC-based fromework to study the effects of running multi-threaded application sofhare on a multiprocessorplatform under the control of one or more abstract real-time operating systems (RTOSS). We propose a modelling framavork consisting of basic RTOS service models; scheduling, synchronization, and resource allocation, and a generic task model fhat is able to model periodic and aperiodic tasks as well as task properties such as varying execution times, offsets, deadlines, and data dependencies. A given multiprocessor system is formed by the composition of RTOSservice models and the allocation of tasks (the application sojiiare) onto RTOSS. We demonstrate the potential ofour approach by simulating and analyzing a small multiprocessor system.
Design Automation for Embedded Systems, 2005
In this paper we present a new approach for automated target code generation for given real-time operating systems out of SystemC to support platform independent software development. Since SystemC becomes the most important language in electronic system level design, the support of a seamless design flow becomes an important task. During the system design process, SystemC is used to develop a "Golden Reference Model" that provides a well-suited platform for specification, simulation, and verification of embedded systems. Based on the "Golden Reference Model," an important task of the design process is to map applications, that have been described either in C++ or directly in SystemC, to the specific real-time operating system which is running at the target processor. Since a manual mapping approach is time-consuming and error-prone, the mapping process should be performed automatically. This paper presents a new method for automated generation of code for a specified operating system just by using an abstract XML representation of the RTOS API.
Design Automation for Embedded Systems, 2005
SystemC is committed to support the requirements for an integrated, HW/SW codesign flow, thus allowing the development of complex, multiprocessing, Systems-on Chip (MpSoC). To make this possible, efficient modeling and simulation methodologies for Real-Time, Embedded (RT/E) SW in SystemC have to be developed, so that the designer can verify and refine the application SW together with the rest of the elements of the platform. Accurate modeling of the application SW requires an accurate model of the RTOS. Nevertheless, low-level, dynamic timing characteristics of the RTOS such as time-slicing, priority-based preemptive scheduling, interrupts and exceptions do not have a direct implementation in SystemC.
IEEE Micro, 2009
RTOS has gained popularity over the years in microcontroller/processor-based embedded system design. In this paper, we will discuss the important differences between RTOS and generic OS, the advantages and disadvantages of using RTOS for small microcontroller system development, and the benchmarking methods used for RTOS. Several RTOSes are studied and compared based upon numerous selection criteria, and four RTOSes are selected for performance benchmarking on the same microcontroller platform. For the purpose of performance benchmarking, a list of benchmarking criteria which is aimed to be simple and representative of typical RTOS usages are examined. The benchmarking results show that there is no clear winner and each RTOS performed well on certain criteria compared to others.
Design, Automation and Test in Europe
This paper presents the methodology and the modeling constructs we have developed to capture the real time aspects of RTOS simulation models in a System Level Design Language (SLDL) like SystemC. We describe these constructs and show how they are used to build a simulation model of an RTOS kernel targeting the µ-ITRON OS specification standard.
An RTOS is a software component that is used in the majority of the real-time embedded systems. It has a significant effect on the system's performance and reliability. This paper addresses the issue of publishing parameterized performance characteristics of an RTOS in a platform independent manner. Concepts of parametric timing analysis were extended to consider the performance of the processor, memory and peripherals in a parameterized way. The proposed method was applied to a commercial RTOS. Validation of the method shows results with a precision better than 10%. Key-words: timing analysis, WCET (Worst Case Execution Time), RTOS (Real-Time Operating System) performance characterization, COTS (Commercial Off The Shelf) software component performance.
Proceedings of the 2005 conference on Asia South Pacific design automation - ASP-DAC '05, 2005
In this paper, we propose a new process definition (T-THREAD) and an extension to the existing SystemC simulation engine (SIM-AF'I library) to capture the real time aspects of RTOS simulation models in an SLDL like SystemC. We describe the execution semantics of this process and show how it works in B complete embedded system simulation model.
Journal of Communication and Computer, 2015
Since their early applications in the 1960s, embedded systems have come down in price and increased dramatically in processing power and functionality. In addition, embedded systems are becoming increasingly complex. High-end devices, such as mobile phones, PDAs, entertainment devices, and set-top boxes, feature millions of lines of code with varying degrees of assurance of correctness. Nowadays, more and more embedded systems are implementing in a distributed way, and a wide range of high-performance distributed embedded systems have been design and deployed. As many aspects of embedded system design become increasingly dependent on the effective interaction of distributed processors, it is clear that much effort needs to be focus on software infrastructure, such as operating systems, to ensure that they provide functionality to fulfill these requirements. This paper reviews some of the approaches associated with the operating systems used to fulfill these needs.
2011
The paper present and compare some real-time control program models used by programmers programming in embedded systems. The paper do not demonstrate all programming models, only the most important variations based on writer's opinion. The writer tried to show the advantages and disadvantages of each programming models discussed in article. The paper begins with traditional models like sequential model, cooperative multitasking and continues with timed cooperative model and finish with event-driven model.
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