WCET Derivation under Single Core Equivalence with Explicit Memory Budget Assignment

Authors Renato Mancuso, Rodolfo Pellizzoni, Neriman Tokcan, Marco Caccamo

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Renato Mancuso
Rodolfo Pellizzoni
Neriman Tokcan
Marco Caccamo

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Renato Mancuso, Rodolfo Pellizzoni, Neriman Tokcan, and Marco Caccamo. WCET Derivation under Single Core Equivalence with Explicit Memory Budget Assignment. In 29th Euromicro Conference on Real-Time Systems (ECRTS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 76, pp. 3:1-3:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


In the last decade there has been a steady uptrend in the popularity of embedded multi-core platforms. This represents a turning point in the theory and implementation of real-time systems. From a real-time standpoint, however, the extensive sharing of hardware resources (e.g. caches, DRAM subsystem, I/O channels) represents a major source of unpredictability. Budget-based memory regulation (throttling) has been extensively studied to enforce a strict partitioning of the DRAM subsystem’s bandwidth. The common approach to analyze a task under memory bandwidth regulation is to consider the budget of the core where the task is executing, and assume the worst-case about the remaining cores' budgets. In this work, we propose a novel analysis strategy to derive the WCET of a task under memory bandwidth regulation that takes into account the exact distribution of memory budgets to cores. In this sense, the proposed analysis represents a generalization of approaches that consider (i) even budget distribution across cores; and (ii) uneven but unknown (except for the core under analysis) budget assignment. By exploiting the additional piece of information, we show that it is possible to derive a more accurate WCET estimation. Our evaluations highlight that the proposed technique can reduce overestimation by 30% in average, and up to 60%, compared to the state of the art.
  • real-time multicore
  • WCET
  • single-core equivalence
  • DRAM management
  • certification


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