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Documents authored by Hoornaert, Denis


Document
Memory Latency Distribution-Driven Regulation for Temporal Isolation in MPSoCs

Authors: Ahsan Saeed, Denis Hoornaert, Dakshina Dasari, Dirk Ziegenbein, Daniel Mueller-Gritschneder, Ulf Schlichtmann, Andreas Gerstlauer, and Renato Mancuso

Published in: LIPIcs, Volume 262, 35th Euromicro Conference on Real-Time Systems (ECRTS 2023)


Abstract
Temporal isolation is one of the most significant challenges that must be addressed before Multi-Processor Systems-on-Chip (MPSoCs) can be widely adopted in mixed-criticality systems with both time-sensitive real-time (RT) applications and performance-oriented non-real-time (NRT) applications. Specifically, the main memory subsystem is one of the most prevalent causes of interference, performance degradation and loss of isolation. Existing memory bandwidth regulation mechanisms use static, dynamic, or predictive DRAM bandwidth management techniques to restore the execution time of an application under contention as close as possible to the execution time in isolation. In this paper, we propose a novel distribution-driven regulation whose goal is to achieve a timeliness objective formulated as a constraint on the probability of meeting a certain target execution time for the RT applications. Using existing interconnect-level Performance Monitoring Units (PMU), we can observe the Cumulative Distribution Function (CDF) of the per-request memory latency. Regulation is then triggered to enforce first-order stochastical dominance with respect to a desired reference. Consequently, it is possible to enforce that the overall observed execution time random variable is dominated by the reference execution time. The mechanism requires no prior information of the contending application and treats the DRAM subsystem as a black box. We provide a full-stack implementation of our mechanism on a Commercial Off-The-Shelf (COTS) platform (Xilinx Ultrascale+ MPSoC), evaluate it using real and synthetic benchmarks, experimentally validate that the timeliness objectives are met for the RT applications, and demonstrate that it is able to provide 2.2x more overall throughput for NRT applications compared to DRAM bandwidth management-based regulation approaches.

Cite as

Ahsan Saeed, Denis Hoornaert, Dakshina Dasari, Dirk Ziegenbein, Daniel Mueller-Gritschneder, Ulf Schlichtmann, Andreas Gerstlauer, and Renato Mancuso. Memory Latency Distribution-Driven Regulation for Temporal Isolation in MPSoCs. In 35th Euromicro Conference on Real-Time Systems (ECRTS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 262, pp. 4:1-4:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{saeed_et_al:LIPIcs.ECRTS.2023.4,
  author =	{Saeed, Ahsan and Hoornaert, Denis and Dasari, Dakshina and Ziegenbein, Dirk and Mueller-Gritschneder, Daniel and Schlichtmann, Ulf and Gerstlauer, Andreas and Mancuso, Renato},
  title =	{{Memory Latency Distribution-Driven Regulation for Temporal Isolation in MPSoCs}},
  booktitle =	{35th Euromicro Conference on Real-Time Systems (ECRTS 2023)},
  pages =	{4:1--4:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-280-8},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{262},
  editor =	{Papadopoulos, Alessandro V.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2023.4},
  URN =		{urn:nbn:de:0030-drops-180339},
  doi =		{10.4230/LIPIcs.ECRTS.2023.4},
  annote =	{Keywords: temporal isolation, memory latency, real-time system, multi-core}
}
Document
Low-Overhead Online Assessment of Timely Progress as a System Commodity

Authors: Weifan Chen, Ivan Izhbirdeev, Denis Hoornaert, Shahin Roozkhosh, Patrick Carpanedo, Sanskriti Sharma, and Renato Mancuso

Published in: LIPIcs, Volume 262, 35th Euromicro Conference on Real-Time Systems (ECRTS 2023)


Abstract
The correctness of safety-critical systems depends on both their logical and temporal behavior. Control-flow integrity (CFI) is a well-established and understood technique to safeguard the logical flow of safety-critical applications. But unfortunately, no established methodologies exist for the complementary problem of detecting violations of control flow timeliness. Worse yet, the latter dimension, which we term Timely Progress Integrity (TPI), is increasingly more jeopardized as the complexity of our embedded systems continues to soar. As key resources of the memory hierarchy become shared by several CPUs and accelerators, they become hard-to-analyze performance bottlenecks. And the precise interplay between software and hardware components becomes hard to predict and reason about. How to restore control over timely progress integrity? We postulate that the first stepping stone toward TPI is to develop methodologies for Timely Progress Assessment (TPA). TPA refers to the ability of a system to live-monitor the positive/negative slack - with respect to a known reference - at key milestones throughout an application’s lifespan. In this paper, we propose one such methodology that goes under the name of Milestone-Based Timely Progress Assessment or MB-TPA, for short. Among the key design principles of MB-TPA is the ability to operate on black-box binary executables with near-zero time overhead and implementable on commercial platforms. To prove its feasibility and effectiveness, we propose and evaluate a full-stack implementation called Timely Progress Assessment with 0 Overhead (TPAw0v). We demonstrate its capability in providing live TPA for complex vision applications while introducing less than 0.6% time overhead for applications under test. Finally, we demonstrate one use case where TPA information is used to restore TPI in the presence of temporal interference over shared memory resources.

Cite as

Weifan Chen, Ivan Izhbirdeev, Denis Hoornaert, Shahin Roozkhosh, Patrick Carpanedo, Sanskriti Sharma, and Renato Mancuso. Low-Overhead Online Assessment of Timely Progress as a System Commodity. In 35th Euromicro Conference on Real-Time Systems (ECRTS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 262, pp. 13:1-13:26, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{chen_et_al:LIPIcs.ECRTS.2023.13,
  author =	{Chen, Weifan and Izhbirdeev, Ivan and Hoornaert, Denis and Roozkhosh, Shahin and Carpanedo, Patrick and Sharma, Sanskriti and Mancuso, Renato},
  title =	{{Low-Overhead Online Assessment of Timely Progress as a System Commodity}},
  booktitle =	{35th Euromicro Conference on Real-Time Systems (ECRTS 2023)},
  pages =	{13:1--13:26},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-280-8},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{262},
  editor =	{Papadopoulos, Alessandro V.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2023.13},
  URN =		{urn:nbn:de:0030-drops-180428},
  doi =		{10.4230/LIPIcs.ECRTS.2023.13},
  annote =	{Keywords: progress-aware regulation, hardware assisted runtime monitoring, timing annotation, control flow graph}
}
Document
A Memory Scheduling Infrastructure for Multi-Core Systems with Re-Programmable Logic

Authors: Denis Hoornaert, Shahin Roozkhosh, and Renato Mancuso

Published in: LIPIcs, Volume 196, 33rd Euromicro Conference on Real-Time Systems (ECRTS 2021)


Abstract
The sharp increase in demand for performance has prompted an explosion in the complexity of modern multi-core embedded systems. This has lead to unprecedented temporal unpredictability concerns in Cyber-Physical Systems (CPS). On-chip integration of programmable logic (PL) alongside a conventional Processing System (PS) in modern Systems-on-Chip (SoC) establishes a genuine compromise between specialization, performance, and reconfigurability. In addition to typical use-cases, it has been shown that the PL can be used to observe, manipulate, and ultimately manage memory traffic generated by a traditional multi-core processor. This paper explores the possibility of PL-aided memory scheduling by proposing a Scheduler In-the-Middle (SchIM). We demonstrate that the SchIM enables transaction-level control over the main memory traffic generated by a set of embedded cores. Focusing on extensibility and reconfigurability, we put forward a SchIM design covering two main objectives. First, to provide a safe playground to test innovative memory scheduling mechanisms; and second, to establish a transition path from software-based memory regulation to provably correct hardware-enforced memory scheduling. We evaluate our design through a full-system implementation on a commercial PS-PL platform using synthetic and real-world benchmarks.

Cite as

Denis Hoornaert, Shahin Roozkhosh, and Renato Mancuso. A Memory Scheduling Infrastructure for Multi-Core Systems with Re-Programmable Logic. In 33rd Euromicro Conference on Real-Time Systems (ECRTS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 196, pp. 2:1-2:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


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@InProceedings{hoornaert_et_al:LIPIcs.ECRTS.2021.2,
  author =	{Hoornaert, Denis and Roozkhosh, Shahin and Mancuso, Renato},
  title =	{{A Memory Scheduling Infrastructure for Multi-Core Systems with Re-Programmable Logic}},
  booktitle =	{33rd Euromicro Conference on Real-Time Systems (ECRTS 2021)},
  pages =	{2:1--2:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-192-4},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{196},
  editor =	{Brandenburg, Bj\"{o}rn B.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2021.2},
  URN =		{urn:nbn:de:0030-drops-139331},
  doi =		{10.4230/LIPIcs.ECRTS.2021.2},
  annote =	{Keywords: Memory Scheduling, PLIM, FPGA, Memory Management, Bandwidth Regulation, MemGuard, Coloring, Bank Partitioning, Real-time, Multicore, Safety-critical}
}
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