Model Driven Engineering provides facilities to tackle complexity in real-timesystems, from early requirements capture to validation & verification down to code generation. We note that models are built from a sy...
详细信息
ISBN:
(纸本)9780769537870
Model Driven Engineering provides facilities to tackle complexity in real-timesystems, from early requirements capture to validation & verification down to code generation. We note that models are built from a system perspective, and resources are allocated to meet communication, energy or scheduling constraints. Yet, it is seldom optimal. In this paper, we explore transformations applied at model-level that preserve schedulability of the system, yet reduce the overall resource consumption. We use A AD L as input formalism. By automating this process, we show how to transition from a system view to an implementation view, closer to actual hardware constraints.
Soft real-time sporadic multiprocessor task systems are considered that include processing pipelines. Conditions are presented for guaranteeing bounded deadline tardiness in such systems under global EDF or FIFO sched...
详细信息
ISBN:
(纸本)9780769537870
Soft real-time sporadic multiprocessor task systems are considered that include processing pipelines. Conditions are presented for guaranteeing bounded deadline tardiness in such systems under global EDF or FIFO scheduling. "Early-releasing" is applied to make pipeline scheduling work-conserving. this lessens job response times in lightly-loaded systems.
Hierarchical scheduling has recently been used to provide temporal isolation to embedded virtualised systems. Response time analysis is a common way to derive a schedulability test these systems. this paper points out...
详细信息
ISBN:
(纸本)9780769537870
Hierarchical scheduling has recently been used to provide temporal isolation to embedded virtualised systems. Response time analysis is a common way to derive a schedulability test these systems. this paper points out that response time analysis for hierarchical fixed-priority scheduling found in the literature is only exact for tasks of the highest priority domain. For the rest of the tasks is an upper bound. In our work, we provide the exact analysis and we compare it with previously published works.
Multi-core platforms are becoming the dominant computing architecture for next generation embeddedsystems. Nevertheless, designing, programming, and analyzing such systems is not easy and a solid methodology is still...
详细信息
ISBN:
(纸本)9780769537870
Multi-core platforms are becoming the dominant computing architecture for next generation embeddedsystems. Nevertheless, designing, programming, and analyzing such systems is not easy and a solid methodology is still missing. In this paper, we propose two powerful abstractions to model the computing power of a parallel machine, which provide a general interface for developing and analyzing real-timeapplications in isolation, independently of the physical platform. the proposed abstractions can be applied on top of different types of service mechanisms, such as periodic servers, static partitions, and P-fair time partitions. In addition, we developed the schedulability analysis of a set of real-time tasks on top of a parallel machine that is compliant withthe proposed abstractions.
Modern processors often provide cache locking capability which can be applied statically and dynamically to manage cache in a predictable manner. the selection of instructions to be locked in the instruction cache (I-...
详细信息
ISBN:
(纸本)9780769537870
Modern processors often provide cache locking capability which can be applied statically and dynamically to manage cache in a predictable manner. the selection of instructions to be locked in the instruction cache (I-Cache) has dramatic influence on the performance of multi-task real-timeembeddedsystems. this paper focuses on using cache locking techniques on a shared I-Cache in a real-timeembedded system with multi-tasks to minimize its worst-case utilization (WCU) which is one of the most important criteria for designing real-timeembeddedsystems. We analyze the static and dynamic strategies to perform I-Cache locking and propose different algorithms which utilize the foreknowing information of the real-timeembeddedapplications. Experiments show that the proposed algorithms can reduce WCU further compared to previous techniques. Design suggestions on which strategy should be utilized under different situations are also induced from the experimental results.
Distributed real-timeembeddedsystems have stringent requirements for key performance properties, such as end-to-end timeliness and reliability, in order to operate properly. In recent years, withthe continuously de...
详细信息
ISBN:
(纸本)9780769537870
Distributed real-timeembeddedsystems have stringent requirements for key performance properties, such as end-to-end timeliness and reliability, in order to operate properly. In recent years, withthe continuously decreasing feature size and increasing demand for computation capabilities, today's real-timeembeddedsystems face an increasing probability of overheating and even thermal failures. As a result, their temperature must be explicitly controlled for improved reliability. While a variety of control algorithms have been proposed for either real-time guarantees or thermal management in an isolated manner;this paper proposes a coordinated control solution that can provide simultaneous thermal and timeliness guarantees for distributed real-timeembeddedsystems running in unpredictable environments. Our control solution features a novel coordination design, which allows the thermal and timeliness control loops to run on their respective desired small timescales for prompt control actions and yet achieve theoretically guaranteed control accuracy and system stability. In addition, while most existing work relies solely on simulations, we present empirical results on a physical testbed to demonstrate the efficacy of our control solution.
Dependable real-lime systems typically consist of tasks of multiple criticality levels and scheduling them in a fault-tolerant manner is a challenging problem. Redundancy in the physical and temporal domains for achie...
详细信息
ISBN:
(纸本)9780769537870
Dependable real-lime systems typically consist of tasks of multiple criticality levels and scheduling them in a fault-tolerant manner is a challenging problem. Redundancy in the physical and temporal domains for achieving fault tolerance has been often dealt independently based on the types of errors one needs to tolerate. To our knowledge, there had been no work which tries to integrate fault tolerant scheduling and multiple redundancy mechanisms. In this paper we propose a novel cascading redundancy approach within a generic fault tolerant scheduling framework. the proposed approach is capable of tolerating errors with a wider coverage (with respect to error frequency and error types) than time and space redundancy in isolation, allows tasks with mixed criticality levels, is independent of the scheduling technique and, above all, ensures that every critical task instance can be feasibly replicated in bothtime and space.
Energy saving is critical to real-timeembeddedsystems. In many embeddedsystems, some tasks contain conditional instructions or operations that could have different execution times for different inputs. Due to the u...
详细信息
ISBN:
(纸本)9780769537870
Energy saving is critical to real-timeembeddedsystems. In many embeddedsystems, some tasks contain conditional instructions or operations that could have different execution times for different inputs. Due to the uncertainties in execution time of these tasks, this paper models each varied execution time as a probabilistic random variable. We propose a practical algorithm to minimize the expected value of total energy consumption while satisfying the timing constraint with a guaranteed confidence probability for uniprocessor embeddedsystems with continuous probability distributions. the experimental results show that our approach achieves significant energy saving than previous work.
this paper presents an efficient best-effort approach for simulation-based timing analysis of complex real-timesystems. the method can handle in principle any software design that can be simulated, and is based on co...
详细信息
ISBN:
(纸本)9780769537870
this paper presents an efficient best-effort approach for simulation-based timing analysis of complex real-timesystems. the method can handle in principle any software design that can be simulated, and is based on controlling simulation input using a simple yet novel hill-climbing algorithm. Unlike previous approaches, the new algorithm directly manipulates simulation parameters such as execution times, arrival jitter and input. An evaluation is presented using six different simulation models, and two other simulation methods as reference: Monte Carlo simulation and MABERA. the new method proposed in this paper was 4-11% more accurate while at the same time 42 times faster on average, than the reference methods.
Static WCET analysis is a process dedicated to derive a safe upper bound of the worst-case execution time of a program. In many real-timesystems, however, a constant global WCET estimate is not always so useful since...
详细信息
ISBN:
(纸本)9780769537870
Static WCET analysis is a process dedicated to derive a safe upper bound of the worst-case execution time of a program. In many real-timesystems, however, a constant global WCET estimate is not always so useful since a program may behave very differently depending on its configuration or mode. A parametric WCET analysis derives the upper bound as formula rather than a constant. this paper presents a new efficient algorithm that can obtain a safe parametric estimate of the WCET of a program. this algorithm is evaluated on a large set of benchmarks and compared to a previous approach to parametric WCET calculation. the evaluation shows that the new algorithm, to the cost of some imprecision, scales much better and can handle more realistic programs than the previous approach.
暂无评论