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Details

  • Name

    João Carlos Barbosa
  • Cluster

    Computer Science
  • Role

    Assistant Researcher
  • Since

    15th March 2021
001
Publications

2022

Hybrid Image-/Data-Parallel Rendering Using Island Parallelism

Authors
Zellmann, S; Wald, I; Barbosa, J; Dermici, S; Sahistan, A; Gudukbay, U;

Publication
2022 IEEE 12TH SYMPOSIUM ON LARGE DATA ANALYSIS AND VISUALIZATION (LDAV 2022)

Abstract
In parallel ray tracing, techniques fall into one of two camps: imageparallel techniques aim at increasing frame rate by replicating scene data across nodes and splitting the rendering work across different ranks, and data-parallel techniques aim at increasing the size of the model that can be rendered by splitting the model across multiple ranks, but typically cannot scale much in frame rate. We propose and evaluate a hybrid approach that combines the advantages of both by splitting a set of N x M ranks into M islands of N ranks each and using data-parallel rendering within each island and image parallelism across islands. We discuss the integration of this concept into four wildly different parallel renderers and evaluate the efficacy of this approach based on multiple different data sets.

2021

LOOM: Interweaving tightly coupled visualization and numeric simulation framework

Authors
Barbosa, J; Navratil, P; Paulo Santos, L; Fussell, D;

Publication
ACM International Conference Proceeding Series

Abstract
Traditional post-hoc high-fidelity scientific visualization (HSV) of numerical simulations requires multiple I/O check-pointing to inspect the simulation progress. The costs of these I/O operations are high and can grow exponentially with increasing problem sizes. In situ HSV dispenses with costly check-pointing I/O operations, but requires additional computing resources to generate the visualization, increasing power and energy consumption. In this paper we present LOOM, a new interweaving approach supported by a task scheduling framework to allow tightly coupled in situ visualization without significantly adding to the overall simulation runtime. The approach exploits the idle times of the numerical simulation threads, due to workload imbalances, to perform the visualization steps. Overall execution time (simulation plus visualization) is minimized. Power requirements are also minimized by sharing the same computational resources among numerical simulation and visualization tasks. We demonstrate that LOOM reduces time to visualization by 3 × compared to a traditional non-interwoven pipeline. Our results here demonstrate good potential for additional gains for large distributed-memory use cases with larger interleaving opportunities. © 2021 ACM.