====== Performance evaluation of a self-clustering heuristic for adaptive PADS ======

====== Authors ======

  * [[https://www.unibo.it/sitoweb/g.dangelo/en|Gabriele D'Angelo]]
  * [[https://www.unibo.it/sitoweb/s.ferretti/en|Stefano Ferretti]]
  * [[https://www.unibo.it/sitoweb/moreno.marzolla/en|Moreno Marzolla]]

====== Abstract ======

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Parallel And Distributed Simulation (PADS) is a well known modeling paradigm that allows efficient implementation of large simulation models as a collection of interacting entities, called Simulated Entities (SEs). SEs can then be assigned to independent execution units for parallel execution, if possible. Allocating SEs to execution units is one of the most challenging problems in PADS: ideally, highly interacting SEs should be placed on the same execution unit so that all communications are local; however, placing too many SEs on the same processor might degrade performance. Furthermore, many simulation models exhibit non-uniform computation and communication patterns among components, that might change during execution at unpredictable times. In this paper we propose a clustering heuristic that exploits communication locality, with the aim to reduce the communication cost experienced by the PADS during the execution. The heuristic adapts automatically to changing interaction patterns by migrating SEs, and can do so without any user-visible modification of the simulation model; there are, however, some parameters that can be used to tune the heuristic. We perform a large set of computational experiments to assess the effectiveness of the heuristic on a real-world scenario, with the aim of guiding the users in selecting optimal values of the heuristic parameters.
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====== Keywords ======

   * Parallel and Distributed Simulation, Discrete Event Simulation, Model Partitioning, Clustering Heuristics.

====== Status ======

   * G. D'Angelo, S. Ferretti and M. Marzolla, "Performance Evaluation of a Self-Clustering Heuristic for Adaptive PADS," 2025 29th International Symposium on Distributed Simulation and Real Time Applications (DS-RT), Prague, Czech Republic, 2025, pp. 1-8, doi: [[https://doi.org/10.1109/DS-RT68115.2025.11185999]].

====== Resources ======

  * Simulation model source code, scripts and raw data are available at [[https://si-clusterraspberry.csr.unibo.it/downloads/Performance_evaluation_of_a_self-clustering_heuristic_for_adaptive_PADS.tgz|this link]]

====== Errata ======

"TABLE I: Simulation model parameters" and the text in "V. PERFORMANCE EVALUATION" ("The simulated area is a toroidal square of 10000 × 10000 space units") describe the simulated space as a toroidal square of fixed size across all simulation configurations. This is incorrect, since the communication model used in the performance evaluation is proximity-based. Therefore, it is important to maintain an approximately constant density of communicating entities in the simulated area. For this reason, the simulated area is scaled according to the number of simulated entities in each evaluated configuration. This can be checked in the model source code provided in the "Resources" section of this page.