Quantitative Characterization of Event Streams in Analysis of Hard Real-Time Applications

Wandeler, Ernesto; Maxiaguine, A.; Thiele, Lothar

doi:10.1007/s11241-005-6885-x

Cited by 39 publications

(33 citation statements)

References 15 publications

(9 reference statements)

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“…This was applied to the context of real-time systems, called Real-Time Calculus first presented in Thiele et al (2000), and has since been extended to handle different system models such as Jonsson et al (2008), Wandeler et al (2004). In approaches based on network calculus, the arrival pattern of jobs of flows is characterized by an arrival curve.…”

Section: Related Workmentioning

confidence: 99%

Reduction-based schedulability analysis of distributed systems with cycles in the task graph

Jayachandran

Abdelzaher

2010

Real-Time Syst

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A significant problem with no simple solutions in current real-time literature is analyzing the end-to-end schedulability of tasks in distributed systems with cycles in the task graph. Prior approaches including network calculus and holistic schedulability analysis work best for acyclic task flows. They involve iterative solutions or offer no solutions at all when flows are non-acyclic. This paper demonstrates the construction of the first generalized closed-form expression for schedulability analysis in distributed task systems with non-acyclic flows. The approach is a significant extension to our previous work on schedulability in Directed Acyclic Graphs. Our main result is a bound on end-to-end delay for a task in a distributed system with non-acyclic task flows. The delay bound allows one of several schedulability tests to be performed. Using the end-to-end delay bound, we extend the delay composition algebra developed for acyclic distributed systems in prior work, to handle loops in the task graph as well. Evaluation shows that the schedulability tests thus constructed are less pessimistic than prior approaches for large distributed systems.

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Section: Related Workmentioning

confidence: 99%

Reduction-based schedulability analysis of distributed systems with cycles in the task graph

Jayachandran

Abdelzaher

2010

Real-Time Syst

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“…The concept of arrival curves to describe the arrival patterns of sets of tasks is well known (request bound functions) and has been used explicitly or implicitly in, e.g. (Baruah 2003) or (Wandeler et al 2005). To simplify the discussion, we limit ourselves to periodic tasks, but the whole formulation allows to deal with much more general classes (sporadic or bursty) as well.…”

Section: Lazy Scheduling Algorithmmentioning

confidence: 99%

Real-time scheduling for energy harvesting sensor nodes

et al. 2007

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Energy harvesting has recently emerged as a feasible option to increase the operating time of sensor networks. If each node of the network, however, is powered by a fluctuating energy source, common power management solutions have to be reconceived. This holds in particular if real-time responsiveness of a given application has to be guaranteed. Task scheduling at the single nodes should account for the properties of the energy source, capacity of the energy storage as well as deadlines of the single tasks. We show that conventional scheduling algorithms (like e.g. EDF) are not suitable for this scenario. Based on this motivation, we have constructed optimal scheduling algorithms that jointly handle constraints from both energy and time domain. Further we present an admittance test that decides for arbitrary task sets, whether they can be scheduled without deadline violations. To this end, we introduce the concept of energy variability characterization curves (EVCC) which nicely captures the dynamics of various energy sources. Simulation results show that our algorithms allow significant reductions of the battery size compared to Earliest Deadline First scheduling.

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“…Resource-based (bright) and event-based (dark) data flows in the analysis of an abstract component. the two blocks labeled WLT, the workload transformations are applied according to (14)- (17), and in the two blocks labeled RTC, (5)-(8) are used to compute outgoing arrival and service curves in the respective base unit.…”

Section: Abstract Components and Workload Transformationsmentioning

confidence: 99%

“…Due to this, there often exist complex correlations in such systems. We can thereby differentiate between correlations in the occurrence of different event types on incoming event streams, which we call event stream correlations (see [17]), and correlations of different resource demands that an event of a given type causes on different system components, which we call workload correlations. Highly correlated resource demands are for example typical in data processing systems, where the resource demand that an event creates on a component directly depends on the size of its payload data.…”

Section: Introductionmentioning

confidence: 99%

“…However, since it is also not capable to capture the above mentioned correlations, that are often present in complex embedded systems, the results obtained from performance analysis with [2] are sometimes overly pessimistic. In [17], a new method was presented that extended the existing framework by allowing to characterize event stream correlations. And in this work, we present a new method that extends the same framework and that allows to characterize, capture and exploit workload correlations in the performance analysis of complex systems.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Workload correlations in multi-processor hard real-time systems

Wandeler¹,

Thiele²

2007

Journal of Computer and System Sciences

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Modern embedded systems that are integrated as multi-processor system on chips, are often characterized by the complex behaviors and dependencies between system components. Different events that trigger such systems may cause different execution demands, depending on their event type as well as on the task they are processed by, leading to complex workload correlations. For example in data processing systems, the size of an event's payload data will typically determine its execution demand on most or all system components, leading to highly correlated workloads. Performance analysis of such systems is often difficult, and conventional analysis methods have no means to capture the possible existence of workload correlations. This leads to overly pessimistic performance analysis results, and thus to expensive system designs with considerable performance reserves. We propose an abstract model to characterize and capture workload correlations present in a system architecture, and we show how the captured additional system information can be incorporated into an existing framework for modular performance analysis of embedded systems.

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Quantitative Characterization of Event Streams in Analysis of Hard Real-Time Applications

Cited by 39 publications

References 15 publications

Reduction-based schedulability analysis of distributed systems with cycles in the task graph

Reduction-based schedulability analysis of distributed systems with cycles in the task graph

Real-time scheduling for energy harvesting sensor nodes

Workload correlations in multi-processor hard real-time systems

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