—In modern non-customized multicore architectures, computing cores commonly share large parts of ... more —In modern non-customized multicore architectures, computing cores commonly share large parts of the memory hierarchy. This paper presents a scheme for controlling the sharing of main memory among cores, respectively the concurrently executing real-time tasks. This is important for the following: concurrent memory accesses are served sequentially by the memory controller. As task execution stalls until memory fetches are served, the latter significantly contributes to the execution time of the tasks. With multiple real-time tasks concurrently competing for the access to the memory, the main memory can easily become the Achilles heel for the timing correctness of the tasks. To provide hard timing guarantees, release of access requests issued to the main memory has therefore to be controlled. Run-time budgeting is a well accepted technique for controlling and coordinating the use of a shared resource, particularly when the underlying hardware cannot be altered. Whilst guaranteeing timing correctness of the hard real-time applications, worst-case based resource budgeting commonly leads to performance degradations of the co-running (so called soft real-time) applications. In this paper we propose to combine worst-case based resource budgeting with run-time monitoring for dynamically re-configuring the budget schemes. Thereby we aim at increasing the responsiveness of the soft real-time applications, while satisfying the strict timing constraints of the co-running hard real-time tasks. We have implemented the proposed scheme in a microker-nel and present its empirical evaluation for which an industrial benchmark suite has been employed.
Component-based validation techniques for parallel and distributed embedded systems should be abl... more Component-based validation techniques for parallel and distributed embedded systems should be able to deal with heterogeneous components, interactions, and specification mech- anisms. This paper describes various approaches that allow the composition of subsystems with different execution and interac- tion semantics by combining computational and analytic models. In particular, this work shows how finite state machines, timed automata, and methods from
This paper describes how to construct complex performability models in the context of the softwar... more This paper describes how to construct complex performability models in the context of the software tool Moebius, by hierarchically composing small submodels. In addition to Moebius' "Join" operator, a second composi- tion operator "Sync" is introduced, and it is shown how both types of composition can be realised on the basis of symbolic, i.e. BDD-based data structures.
Proceedings of the seventh IEEE/ACM/IFIP international conference on Hardware/software codesign and system synthesis - CODES+ISSS '11, 2011
Energy consumption has become an important issue for modern embedded systems. This is because, on... more Energy consumption has become an important issue for modern embedded systems. This is because, one does not only like to deploy high-performance systems and provide guaranteed services, but also request system deployments to last as long as possible. With online dynamic power management (DPM), one adaptively changes the system's power mode, i.e., schedules when to turn on and off on-the-fly,
—In modern non-customized multicore architectures, computing cores commonly share large parts of ... more —In modern non-customized multicore architectures, computing cores commonly share large parts of the memory hierarchy. This paper presents a scheme for controlling the sharing of main memory among cores, respectively the concurrently executing real-time tasks. This is important for the following: concurrent memory accesses are served sequentially by the memory controller. As task execution stalls until memory fetches are served, the latter significantly contributes to the execution time of the tasks. With multiple real-time tasks concurrently competing for the access to the memory, the main memory can easily become the Achilles heel for the timing correctness of the tasks. To provide hard timing guarantees, release of access requests issued to the main memory has therefore to be controlled. Run-time budgeting is a well accepted technique for controlling and coordinating the use of a shared resource, particularly when the underlying hardware cannot be altered. Whilst guaranteeing timing correctness of the hard real-time applications, worst-case based resource budgeting commonly leads to performance degradations of the co-running (so called soft real-time) applications. In this paper we propose to combine worst-case based resource budgeting with run-time monitoring for dynamically re-configuring the budget schemes. Thereby we aim at increasing the responsiveness of the soft real-time applications, while satisfying the strict timing constraints of the co-running hard real-time tasks. We have implemented the proposed scheme in a microker-nel and present its empirical evaluation for which an industrial benchmark suite has been employed.
Component-based validation techniques for parallel and distributed embedded systems should be abl... more Component-based validation techniques for parallel and distributed embedded systems should be able to deal with heterogeneous components, interactions, and specification mech- anisms. This paper describes various approaches that allow the composition of subsystems with different execution and interac- tion semantics by combining computational and analytic models. In particular, this work shows how finite state machines, timed automata, and methods from
This paper describes how to construct complex performability models in the context of the softwar... more This paper describes how to construct complex performability models in the context of the software tool Moebius, by hierarchically composing small submodels. In addition to Moebius' "Join" operator, a second composi- tion operator "Sync" is introduced, and it is shown how both types of composition can be realised on the basis of symbolic, i.e. BDD-based data structures.
Proceedings of the seventh IEEE/ACM/IFIP international conference on Hardware/software codesign and system synthesis - CODES+ISSS '11, 2011
Energy consumption has become an important issue for modern embedded systems. This is because, on... more Energy consumption has become an important issue for modern embedded systems. This is because, one does not only like to deploy high-performance systems and provide guaranteed services, but also request system deployments to last as long as possible. With online dynamic power management (DPM), one adaptively changes the system's power mode, i.e., schedules when to turn on and off on-the-fly,
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Papers by Kai Lampka