CPSLab Cyber-Physical Systems Lab, Boston University

Publications Memory & Shared-Resource Management

Profile-driven memory bandwidth management for accelerators and CPUs in QoS-enabled platforms

Parul Sohal, Rohan Tabish, Ulrich Drepper, Renato Mancuso

Real-Time Systems, December 2022

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Fig. 1: Overview of main parameters in the E-WarP model for a generic task τ i executing on CP U 1 and ACC 1 .

Abstract

The proliferation of multi-core, accelerator-enabled embedded systems has introduced new opportunities to consolidate real-time systems of increasing complexity. But the road to build confidence on the temporal behavior of co-running applications has presented formidable challenges. Most prominently, the main memory subsystem represents a performance bottleneck for both CPUs and accelerators. And industry-viable frameworks for full-system main memory management and performance analysis are past due. In this paper, we propose our Envelope-aWare Predictive model , or E-WarP for short. E-WarP is a methodology and technological framework to: (1) analyze the memory demand of applications following a profile-driven approach; (2) make realistic predictions on the temporal behavior of workload deployed on CPUs and accelerators; and (3) perform saturation-aware system consolidation. This work aims at providing the technological foundations as well as the theoretical grassroots for truly workload-aware analysis of real-time systems. This work combines traditional CPU-centric bandwidth regulation techniques with state-of-the-art hardware support for memory traffic shaping via the ARM QoS extensions. We make three key observations. First, our profile-driven methodology achieves, on average, 6% over-prediction on the runtime of bandwidth-regulated applications. Second, we experimentally validate that the calculated bounds hold system-wide if the main memory subsystem operates below saturation. Third, we show that the E-WarP methodology is practical even when applications exhibit input-dependent memory access patterns. We provide a full implementation of our techniques on a commercial platform (NXP S32V234).

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Cite this paper

@article{profile_QoS_RTSJ22,
  title     = {{Profile-driven memory bandwidth management for accelerators and CPUs in QoS-enabled platforms}},
  author    = {Sohal, Parul and Tabish, Rohan and Drepper, Ulrich and Mancuso, Renato},
  journal   = {Real-Time Systems},
  year      = 2022,
  month     = dec,
  publisher = {Springer},
  doi       = {10.1007/s11241-022-09382-x},
  url       = {https://doi.org/10.1007/s11241-022-09382-x}
}

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