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Documents authored by Pellizzoni, Rodolfo


Document
Multi-Objective Memory Bandwidth Regulation and Cache Partitioning for Multicore Real-Time Systems

Authors: Binqi Sun, Zhihang Wei, Andrea Bastoni, Debayan Roy, Mirco Theile, Tomasz Kloda, Rodolfo Pellizzoni, and Marco Caccamo

Published in: LIPIcs, Volume 335, 37th Euromicro Conference on Real-Time Systems (ECRTS 2025)


Abstract
Memory bandwidth regulation and cache partitioning are widely used techniques for achieving predictable timing in real-time computing systems. Combined with partitioned scheduling, these methods require careful co-allocation of tasks and resources to cores, as task execution times strongly depend on available allocated resources. To address this challenge, this paper presents a 0-1 linear program for task-resource co-allocation, along with a multi-objective heuristic designed to minimize resource usage while guaranteeing schedulability under a preemptive EDF scheduling policy. Our heuristic employs a multi-layer framework, where an outer layer explores resource allocations using Pareto-pruned search, and an inner layer optimizes task allocation by solving a knapsack problem using dynamic programming. To evaluate the performance of the proposed optimization algorithm, we profile real-world benchmarks on an embedded AMD UltraScale+ ZCU102 platform, with fine-grained resource partitioning enabled by the Jailhouse hypervisor, leveraging cache set partitioning and MemGuard for memory bandwidth regulation. Experiments based on the benchmarking results show that the proposed 0-1 linear program outperforms existing mixed-integer programs by finding more optimal solutions within the same time limit. Moreover, the proposed multi-objective multi-layer heuristic performs consistently better than the state-of-the-art multi-resource-task co-allocation algorithm in terms of schedulability, resource usage, number of non-dominated solutions, and computational efficiency.

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Binqi Sun, Zhihang Wei, Andrea Bastoni, Debayan Roy, Mirco Theile, Tomasz Kloda, Rodolfo Pellizzoni, and Marco Caccamo. Multi-Objective Memory Bandwidth Regulation and Cache Partitioning for Multicore Real-Time Systems. In 37th Euromicro Conference on Real-Time Systems (ECRTS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 335, pp. 2:1-2:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)


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@InProceedings{sun_et_al:LIPIcs.ECRTS.2025.2,
  author =	{Sun, Binqi and Wei, Zhihang and Bastoni, Andrea and Roy, Debayan and Theile, Mirco and Kloda, Tomasz and Pellizzoni, Rodolfo and Caccamo, Marco},
  title =	{{Multi-Objective Memory Bandwidth Regulation and Cache Partitioning for Multicore Real-Time Systems}},
  booktitle =	{37th Euromicro Conference on Real-Time Systems (ECRTS 2025)},
  pages =	{2:1--2:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-377-5},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{335},
  editor =	{Mancuso, Renato},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2025.2},
  URN =		{urn:nbn:de:0030-drops-235807},
  doi =		{10.4230/LIPIcs.ECRTS.2025.2},
  annote =	{Keywords: Multi-objective optimization, memory bandwidth regulation, cache partitioning, partitioned scheduling, real-time systems}
}
Document
DAMA: A Dual Arbitration Mechanism for Mixed-Criticality Applications

Authors: Wafic Lawand and Rodolfo Pellizzoni

Published in: LIPIcs, Volume 335, 37th Euromicro Conference on Real-Time Systems (ECRTS 2025)


Abstract
We discuss hardware resource management in mixed-criticality systems, where requestors may issue latency-critical (LTC) and non-latency-critical (NLTC) requests. LTC requests must adhere to strict latency bounds imposed by safety-critical applications, but timely servicing NLTC requests is necessary to maximize overall system performance in the average case. In this paper, we address this tradeoff for a shared memory resource by proposing DAMA, a dual arbitration mechanism that imposes an upper bound on the cumulative latency of LTC requests without unduly impacting NLTC performance. DAMA comprises a high-performance arbiter, a real-time arbiter, and a mechanism that constantly monitors the cumulative latency of requests suffered by each requestor. DAMA primarily executes in high-performance mode and only switches to real-time mode in the rare instances when its incorporated mechanism detects a violation of a task’s timing guarantee. We demonstrate the effectiveness of our arbitration scheme by adapting a predictable prefetcher that issues NLTC requests and attaching it to the L1 caches of our cores. We show both formally and experimentally that DAMA provides timing guarantees for LTC requests while processing other NLTC requests. We also demonstrate that with a negligible overhead of less than 1.5% on the cumulative latency bound of LTC requests, DAMA can achieve an equivalent average performance to a prefetcher that processes requests under a high-performance arbitration scheme.

Cite as

Wafic Lawand and Rodolfo Pellizzoni. DAMA: A Dual Arbitration Mechanism for Mixed-Criticality Applications. In 37th Euromicro Conference on Real-Time Systems (ECRTS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 335, pp. 9:1-9:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)


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@InProceedings{lawand_et_al:LIPIcs.ECRTS.2025.9,
  author =	{Lawand, Wafic and Pellizzoni, Rodolfo},
  title =	{{DAMA: A Dual Arbitration Mechanism for Mixed-Criticality Applications}},
  booktitle =	{37th Euromicro Conference on Real-Time Systems (ECRTS 2025)},
  pages =	{9:1--9:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-377-5},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{335},
  editor =	{Mancuso, Renato},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2025.9},
  URN =		{urn:nbn:de:0030-drops-235875},
  doi =		{10.4230/LIPIcs.ECRTS.2025.9},
  annote =	{Keywords: Real-time Systems, Mixed-criticality Applications, Memory controllers, Prefetchers}
}
Document
Complete Volume
LIPIcs, Volume 298, ECRTS 2024, Complete Volume

Authors: Rodolfo Pellizzoni

Published in: LIPIcs, Volume 298, 36th Euromicro Conference on Real-Time Systems (ECRTS 2024)


Abstract
LIPIcs, Volume 298, ECRTS 2024, Complete Volume

Cite as

36th Euromicro Conference on Real-Time Systems (ECRTS 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 298, pp. 1-436, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)


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@Proceedings{pellizzoni:LIPIcs.ECRTS.2024,
  title =	{{LIPIcs, Volume 298, ECRTS 2024, Complete Volume}},
  booktitle =	{36th Euromicro Conference on Real-Time Systems (ECRTS 2024)},
  pages =	{1--436},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-324-9},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{298},
  editor =	{Pellizzoni, Rodolfo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2024},
  URN =		{urn:nbn:de:0030-drops-203024},
  doi =		{10.4230/LIPIcs.ECRTS.2024},
  annote =	{Keywords: LIPIcs, Volume 298, ECRTS 2024, Complete Volume}
}
Document
Front Matter
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Rodolfo Pellizzoni

Published in: LIPIcs, Volume 298, 36th Euromicro Conference on Real-Time Systems (ECRTS 2024)


Abstract
Front Matter, Table of Contents, Preface, Conference Organization

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36th Euromicro Conference on Real-Time Systems (ECRTS 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 298, pp. 0:i-0:xiv, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)


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@InProceedings{pellizzoni:LIPIcs.ECRTS.2024.0,
  author =	{Pellizzoni, Rodolfo},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{36th Euromicro Conference on Real-Time Systems (ECRTS 2024)},
  pages =	{0:i--0:xiv},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-324-9},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{298},
  editor =	{Pellizzoni, Rodolfo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2024.0},
  URN =		{urn:nbn:de:0030-drops-203034},
  doi =		{10.4230/LIPIcs.ECRTS.2024.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
A Tight Holistic Memory Latency Bound Through Coordinated Management of Memory Resources

Authors: Shorouk Abdelhalim, Danesh Germchi, Mohamed Hossam, Rodolfo Pellizzoni, and Mohamed Hassan

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


Abstract
To facilitate the safe adoption of multi-core platforms in real-time systems, a plethora of recent research efforts aim at bounding the delays induced by interference upon accessing the shared memory resources in these platforms. These efforts, despite their value, are scattered, with each one focusing solely on only one of these resources with the premise that latency bounds separately driven for each resource can be added all together to provide a safe end-to-end memory bound. In this work, we put this assumption to the test for the first time by 1) considering a realistic multi-core memory hierarchy system, 2) deriving the bounds for accessing the shared resources in this system, and 3) highlighting the limitations of this widely-adopted approach. In particular, we show that this approach leads to not only excessively pessimistic but also unsafe bounds. Motivated by these findings, we propose GRROF: a novel approach to predictably and efficiently schedule memory requests while traversing the entire memory hierarchy through coordination among arbiters managing all the resources in this hierarchy. By virtue of this novel mechanism, we managed to exploit pipelining upon analyzing the latency of the memory requests for tightly bounding the worst-case latency. We prove in the paper that GRROF enables us to derive a drastically tighter bound compared to the common additive latency approach with more than 18× reduction in the end-to-end memory latency bound for a modern Out-of-Order quad-core platform. The reduction is further improved significantly with the increase in the number of cores. The proposed solution is fully prototyped and tested in a cycle-accurate simulation. We also compare it with real-time competitive state-of-the-art and performance-oriented solutions existing in modern Commercial-off-the-Shelf (COTS) platforms.

Cite as

Shorouk Abdelhalim, Danesh Germchi, Mohamed Hossam, Rodolfo Pellizzoni, and Mohamed Hassan. A Tight Holistic Memory Latency Bound Through Coordinated Management of Memory Resources. In 35th Euromicro Conference on Real-Time Systems (ECRTS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 262, pp. 17:1-17:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{abdelhalim_et_al:LIPIcs.ECRTS.2023.17,
  author =	{Abdelhalim, Shorouk and Germchi, Danesh and Hossam, Mohamed and Pellizzoni, Rodolfo and Hassan, Mohamed},
  title =	{{A Tight Holistic Memory Latency Bound Through Coordinated Management of Memory Resources}},
  booktitle =	{35th Euromicro Conference on Real-Time Systems (ECRTS 2023)},
  pages =	{17:1--17:25},
  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.2023.17},
  URN =		{urn:nbn:de:0030-drops-180463},
  doi =		{10.4230/LIPIcs.ECRTS.2023.17},
  annote =	{Keywords: Predictability, Main Memory, Caches, Real-time}
}
Document
Parallelism-Aware High-Performance Cache Coherence with Tight Latency Bounds

Authors: Reza Mirosanlou, Mohamed Hassan, and Rodolfo Pellizzoni

Published in: LIPIcs, Volume 231, 34th Euromicro Conference on Real-Time Systems (ECRTS 2022)


Abstract
In Commercial-Off-The-Shelf (COTS) systems-on-chip, processing elements communicate data through a shared memory hierarchy, and a coherent high-performance interconnect, where the de facto standard to handle shared data is through a coherence protocol. Driven by the extraordinary demands from modern real-time embedded system applications to generate, process, and communicate massive amounts of data, recent efforts aim to ensure timing predictability while integrating cache coherence in multi-core real-time systems. However, we observe that most of these efforts compromise system average performance upon offering predictability guarantees. Motivated by this observation, this work proposes an arbiter aimed at providing a predictable, coherent shared cache hierarchy solution, yet with a negligible performance degradation compared to COTS solutions. We achieve this goal by adopting a high-performance-driven architecture including a split-transaction bus and bankized shared cache. In addition, all accesses are arbitrated through a global ordering mechanism. Our proposed arbiter operates alongside conventional coherence protocols without requiring any protocol modifications. Furthermore, we leverage the Duetto reference model by pairing the proposed arbiter and a high-performance arbiter. We evaluate our solution based on both synthetic and SPLASH-3 benchmarks, showing that we can significantly outperform the state-of-the-art in predictable cache coherence, while offering a COTS-level performance.

Cite as

Reza Mirosanlou, Mohamed Hassan, and Rodolfo Pellizzoni. Parallelism-Aware High-Performance Cache Coherence with Tight Latency Bounds. In 34th Euromicro Conference on Real-Time Systems (ECRTS 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 231, pp. 16:1-16:27, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{mirosanlou_et_al:LIPIcs.ECRTS.2022.16,
  author =	{Mirosanlou, Reza and Hassan, Mohamed and Pellizzoni, Rodolfo},
  title =	{{Parallelism-Aware High-Performance Cache Coherence with Tight Latency Bounds}},
  booktitle =	{34th Euromicro Conference on Real-Time Systems (ECRTS 2022)},
  pages =	{16:1--16:27},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-239-6},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{231},
  editor =	{Maggio, Martina},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2022.16},
  URN =		{urn:nbn:de:0030-drops-163330},
  doi =		{10.4230/LIPIcs.ECRTS.2022.16},
  annote =	{Keywords: Predictability, Cache, COTS, Arbitration, Real-time system}
}
Document
Analysis of Memory-Contention in Heterogeneous COTS MPSoCs

Authors: Mohamed Hassan and Rodolfo Pellizzoni

Published in: LIPIcs, Volume 165, 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)


Abstract
Multiple-Processors Systems-on-Chip (MPSoCs) provide an appealing platform to execute Mixed Criticality Systems (MCS) with both time-sensitive critical tasks and performance-oriented non-critical tasks. Their heterogeneity with a variety of processing elements can address the conflicting requirements of those tasks. Nonetheless, the complex (and hence hard-to-analyze) architecture of Commercial-Off-The-Shelf (COTS) MPSoCs presents a challenge encumbering their adoption for MCS. In this paper, we propose a framework to analyze the memory contention in COTS MPSoCs and provide safe and tight bounds to the delays suffered by any critical task due to this contention. Unlike existing analyses, our solution is based on two main novel approaches. 1) It conducts a hybrid analysis that blends both request-level and task-level analyses into the same framework. 2) It leverages available knowledge about the types of memory requests of the task under analysis as well as contending tasks; specifically, we consider information that is already obtainable by applying existing static analysis tools to each task in isolation. Thanks to these novel techniques, our comparisons with the state-of-the art approaches show that the proposed analysis provides the tightest bounds across all evaluated access scenarios.

Cite as

Mohamed Hassan and Rodolfo Pellizzoni. Analysis of Memory-Contention in Heterogeneous COTS MPSoCs. In 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 165, pp. 23:1-23:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{hassan_et_al:LIPIcs.ECRTS.2020.23,
  author =	{Hassan, Mohamed and Pellizzoni, Rodolfo},
  title =	{{Analysis of Memory-Contention in Heterogeneous COTS MPSoCs}},
  booktitle =	{32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)},
  pages =	{23:1--23:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-152-8},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{165},
  editor =	{V\"{o}lp, Marcus},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2020.23},
  URN =		{urn:nbn:de:0030-drops-123861},
  doi =		{10.4230/LIPIcs.ECRTS.2020.23},
  annote =	{Keywords: DRAM, Memory, COTS, Multi-core, Real-Time, Embedded Systems, Analysis}
}
Document
PREM-Based Optimal Task Segmentation Under Fixed Priority Scheduling

Authors: Muhammad R. Soliman and Rodolfo Pellizzoni

Published in: LIPIcs, Volume 133, 31st Euromicro Conference on Real-Time Systems (ECRTS 2019)


Abstract
Recently, a large number of works have discussed scheduling tasks consisting of a sequence of memory phases, where code and data are moved between main memory and local memory, and computation phases, where the task executes based on the content of local memory only; the key idea is to prevent main memory contention by scheduling the memory phase of one task in parallel with computation phases of tasks running on other cores. This paper provides two main contributions: (1) we present a compiler-level tool, based on the LLVM intermediate representation, that automatically converts a program into a conditional sequence of segments comprising memory and computation phases; (2) we propose an algorithm to find optimal segmentation decisions for a task set scheduled according to a fixed-priority partitioned scheme. Our evaluation shows that the proposed framework can be feasibly applied to realistic programs, and vastly overperforms a baseline greedy approach.

Cite as

Muhammad R. Soliman and Rodolfo Pellizzoni. PREM-Based Optimal Task Segmentation Under Fixed Priority Scheduling. In 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 133, pp. 4:1-4:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{soliman_et_al:LIPIcs.ECRTS.2019.4,
  author =	{Soliman, Muhammad R. and Pellizzoni, Rodolfo},
  title =	{{PREM-Based Optimal Task Segmentation Under Fixed Priority Scheduling}},
  booktitle =	{31st Euromicro Conference on Real-Time Systems (ECRTS 2019)},
  pages =	{4:1--4:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-110-8},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{133},
  editor =	{Quinton, Sophie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2019.4},
  URN =		{urn:nbn:de:0030-drops-107417},
  doi =		{10.4230/LIPIcs.ECRTS.2019.4},
  annote =	{Keywords: PREM, LLVM, scratchpad memory, scheduling, program segmentation}
}
Document
Designing Mixed Criticality Applications on Modern Heterogeneous MPSoC Platforms

Authors: Giovani Gracioli, Rohan Tabish, Renato Mancuso, Reza Mirosanlou, Rodolfo Pellizzoni, and Marco Caccamo

Published in: LIPIcs, Volume 133, 31st Euromicro Conference on Real-Time Systems (ECRTS 2019)


Abstract
Multiprocessor Systems-on-Chip (MPSoC) integrating hard processing cores with programmable logic (PL) are becoming increasingly common. While these platforms have been originally designed for high performance computing applications, their rich feature set can be exploited to efficiently implement mixed criticality domains serving both critical hard real-time tasks, as well as soft real-time tasks. In this paper, we take a deep look at commercially available heterogeneous MPSoCs that incorporate PL and a multicore processor. We show how one can tailor these processors to support a mixed criticality system, where cores are strictly isolated to avoid contention on shared resources such as Last-Level Cache (LLC) and main memory. In order to avoid conflicts in last-level cache, we propose the use of cache coloring, implemented in the Jailhouse hypervisor. In addition, we employ ScratchPad Memory (SPM) inside the PL to support a multi-phase execution model for real-time tasks that avoids conflicts in shared memory. We provide a full-stack, working implementation on a latest-generation MPSoC platform, and show results based on both a set of data intensive tasks, as well as a case study based on an image processing benchmark application.

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Giovani Gracioli, Rohan Tabish, Renato Mancuso, Reza Mirosanlou, Rodolfo Pellizzoni, and Marco Caccamo. Designing Mixed Criticality Applications on Modern Heterogeneous MPSoC Platforms. In 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 133, pp. 27:1-27:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{gracioli_et_al:LIPIcs.ECRTS.2019.27,
  author =	{Gracioli, Giovani and Tabish, Rohan and Mancuso, Renato and Mirosanlou, Reza and Pellizzoni, Rodolfo and Caccamo, Marco},
  title =	{{Designing Mixed Criticality Applications on Modern Heterogeneous MPSoC Platforms}},
  booktitle =	{31st Euromicro Conference on Real-Time Systems (ECRTS 2019)},
  pages =	{27:1--27:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-110-8},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{133},
  editor =	{Quinton, Sophie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2019.27},
  URN =		{urn:nbn:de:0030-drops-107645},
  doi =		{10.4230/LIPIcs.ECRTS.2019.27},
  annote =	{Keywords: Mixed-criticality systems, SoC Heterogeneous platforms, FPGA, real-time computing}
}
Document
WCET Derivation under Single Core Equivalence with Explicit Memory Budget Assignment

Authors: Renato Mancuso, Rodolfo Pellizzoni, Neriman Tokcan, and Marco Caccamo

Published in: LIPIcs, Volume 76, 29th Euromicro Conference on Real-Time Systems (ECRTS 2017)


Abstract
In the last decade there has been a steady uptrend in the popularity of embedded multi-core platforms. This represents a turning point in the theory and implementation of real-time systems. From a real-time standpoint, however, the extensive sharing of hardware resources (e.g. caches, DRAM subsystem, I/O channels) represents a major source of unpredictability. Budget-based memory regulation (throttling) has been extensively studied to enforce a strict partitioning of the DRAM subsystem’s bandwidth. The common approach to analyze a task under memory bandwidth regulation is to consider the budget of the core where the task is executing, and assume the worst-case about the remaining cores' budgets. In this work, we propose a novel analysis strategy to derive the WCET of a task under memory bandwidth regulation that takes into account the exact distribution of memory budgets to cores. In this sense, the proposed analysis represents a generalization of approaches that consider (i) even budget distribution across cores; and (ii) uneven but unknown (except for the core under analysis) budget assignment. By exploiting the additional piece of information, we show that it is possible to derive a more accurate WCET estimation. Our evaluations highlight that the proposed technique can reduce overestimation by 30% in average, and up to 60%, compared to the state of the art.

Cite as

Renato Mancuso, Rodolfo Pellizzoni, Neriman Tokcan, and Marco Caccamo. WCET Derivation under Single Core Equivalence with Explicit Memory Budget Assignment. In 29th Euromicro Conference on Real-Time Systems (ECRTS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 76, pp. 3:1-3:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{mancuso_et_al:LIPIcs.ECRTS.2017.3,
  author =	{Mancuso, Renato and Pellizzoni, Rodolfo and Tokcan, Neriman and Caccamo, Marco},
  title =	{{WCET Derivation under Single Core Equivalence with Explicit Memory Budget Assignment}},
  booktitle =	{29th Euromicro Conference on Real-Time Systems (ECRTS 2017)},
  pages =	{3:1--3:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-037-8},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{76},
  editor =	{Bertogna, Marko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2017.3},
  URN =		{urn:nbn:de:0030-drops-71684},
  doi =		{10.4230/LIPIcs.ECRTS.2017.3},
  annote =	{Keywords: real-time multicore, WCET, single-core equivalence, DRAM management, certification}
}
Document
Contego: An Adaptive Framework for Integrating Security Tasks in Real-Time Systems

Authors: Monowar Hasan, Sibin Mohan, Rodolfo Pellizzoni, and Rakesh B. Bobba

Published in: LIPIcs, Volume 76, 29th Euromicro Conference on Real-Time Systems (ECRTS 2017)


Abstract
Embedded real-time systems (RTS) are pervasive. Many modern RTS are exposed to unknown security flaws, and threats to RTS are growing in both number and sophistication. However, until recently, cyber-security considerations were an afterthought in the design of such systems. Any security mechanisms integrated into RTS must (a) co-exist with the real-time tasks in the system and (b) operate without impacting the timing and safety constraints of the control logic. We introduce Contego, an approach to integrating security tasks into RTS without affecting temporal requirements. Contego is specifically designed for legacy systems, viz., the real-time control systems in which major alterations of the system parameters for constituent tasks is not always feasible. Contego combines the concept of opportunistic execution with hierarchical scheduling to maintain compatibility with legacy systems while still providing flexibility by allowing security tasks to operate in different modes. We also define a metric to measure the effectiveness of such integration. We evaluate Contego using synthetic workloads as well as with an implementation on a realistic embedded platform (an open-source ARM CPU running real-time Linux).

Cite as

Monowar Hasan, Sibin Mohan, Rodolfo Pellizzoni, and Rakesh B. Bobba. Contego: An Adaptive Framework for Integrating Security Tasks in Real-Time Systems. In 29th Euromicro Conference on Real-Time Systems (ECRTS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 76, pp. 23:1-23:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{hasan_et_al:LIPIcs.ECRTS.2017.23,
  author =	{Hasan, Monowar and Mohan, Sibin and Pellizzoni, Rodolfo and Bobba, Rakesh B.},
  title =	{{Contego: An Adaptive Framework for Integrating Security Tasks in Real-Time Systems}},
  booktitle =	{29th Euromicro Conference on Real-Time Systems (ECRTS 2017)},
  pages =	{23:1--23:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-037-8},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{76},
  editor =	{Bertogna, Marko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2017.23},
  URN =		{urn:nbn:de:0030-drops-71728},
  doi =		{10.4230/LIPIcs.ECRTS.2017.23},
  annote =	{Keywords: Real-Time Systems, Security, Hierarchical Scheduling}
}
Document
WCET-Driven Dynamic Data Scratchpad Management With Compiler-Directed Prefetching

Authors: Muhammad Refaat Soliman and Rodolfo Pellizzoni

Published in: LIPIcs, Volume 76, 29th Euromicro Conference on Real-Time Systems (ECRTS 2017)


Abstract
In recent years, the real-time community has produced a variety of approaches targeted at managing on-chip memory (scratchpads and caches) in a predictable way. However, to obtain safe WCET bounds, such techniques generally assume that the processor is stalled while waiting to reload the content of the on-chip memory; hence, they are less effective at hiding main memory latency compared to speculation-based techniques, such as hardware prefetching, that are largely used in general-purpose systems. In this work, we introduce a novel compiler-directed prefetching scheme for scratchpad memory that effectively hides the latency of main memory accesses by overlapping data transfers with the program execution. We implement and test an automated program compilation and optimization flow within the LLVM framework, and we show how to obtain improved WCET bounds through static analysis.

Cite as

Muhammad Refaat Soliman and Rodolfo Pellizzoni. WCET-Driven Dynamic Data Scratchpad Management With Compiler-Directed Prefetching. In 29th Euromicro Conference on Real-Time Systems (ECRTS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 76, pp. 24:1-24:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


Copy BibTex To Clipboard

@InProceedings{soliman_et_al:LIPIcs.ECRTS.2017.24,
  author =	{Soliman, Muhammad Refaat and Pellizzoni, Rodolfo},
  title =	{{WCET-Driven Dynamic Data Scratchpad Management With Compiler-Directed Prefetching}},
  booktitle =	{29th Euromicro Conference on Real-Time Systems (ECRTS 2017)},
  pages =	{24:1--24:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-037-8},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{76},
  editor =	{Bertogna, Marko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2017.24},
  URN =		{urn:nbn:de:0030-drops-71756},
  doi =		{10.4230/LIPIcs.ECRTS.2017.24},
  annote =	{Keywords: scratchpad, LLVM, prefetching, real-time, genetic algorithm}
}
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