Worst-Case Communication Delay Analysis for NoC-Based Many-Cores Using a Limited Migrative Model

A steady increase in the number of cores within many-core platforms causes increasing contentions for the interconnect medium and leads to non-negligible latencies of the inter-core communication. In order to study the worst-case execution times of applications, it is no longer sufficient to only take into account their schedulability requirements, but the communication delays also have to be considered. In this work, we focus on the worst-case communication delays of applications, deployed upon a NoC-based many-core platform using a Limited Migrative Model (LMM). The LMM approach is based on the multi-kernel paradigm, which is a promising step towards scalable and predictable many-cores. The contribution of this work is threefold. First, we extend LMM by allowing the inter-application communication, and subsequently adapt the existing method for the worst-case communication delay analysis, so as to make it applicable to the enhanced model. Then, we propose a novel method. Finally, we compare these two approaches. The experiments show that the new technique renders tighter upper-bound estimates in more than 90% of the cases, and also demonstrates a comparable runtime performance. J Sign Process Syst (2016) 84:25–46 DOI 10.1007/s11265-015-0992-6 Worst-Case Communication Delay Analysis for NoC-Based Many-Cores Using a Limited Migrative Model Borislav Nikolić · Patrick Meumeu Yomsi · Stefan M. Petters Received: 11 October 2014 / Revised: 26 February 2015 / Accepted: 6 March 2015 / Published online: 14 April 2015 © Springer Science+Business Media New York 2015 Abstract A steady increase in the number of cores withinA steady increase in the number of cores within many-core platforms causes increasing contentions for the interconnect medium and leads to non-negligible latencies of the inter-core communication. In order to study the worst-case execution times of applications, it is no longer sufficient to only take into account their schedulability requirements, but the communication delays also have to be considered. In this work, we focus on the worstcase communication delays of applications, deployed upon a NoC-based many-core platform using a Limited Migrative Model (LMM). The LMM approach is based on the multi-kernel paradigm, which is a promising step towards scalable and predictable many-cores. The contribution of this work is threefold. First, we extend LMM by allowing the inter-application communication, and subsequently adapt the existing method for the worst-case communication delay analysis, so as to make it applicable to the enhanced model. Then, we propose a novel method. Finally, we compare these two approaches. The experiments show that the new technique renders tighter upper-bound estimates in more than 90 % of the cases, and also demonstrates a comparable runtime performance. B. Nikolić ( ) · P. M. Yomsi · S. M. Petters CISTER/INESC-TEC, ISEP, IPP, Rua Dr. Antnio Bernardino de Almeida 431, 4200-072 Porto, Portugal e-mail: [email protected] P. M. Yomsi e-mail: [email protected] S. M. Petters e-mail: [email protected]