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Documents authored by Caccamo, Marco

Document
DOI: 10.4230/LIPIcs.ECRTS.2024.17
Response Time Analysis for Fixed-Priority Preemptive Uniform Multiprocessor Systems

Authors: Binqi Sun, Tomasz Kloda, and Marco Caccamo

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

Abstract
We present a response time analysis for global fixed-priority preemptive scheduling of constrained-deadline tasks upon a uniform multiprocessor where each processor can be characterized by a different speed. A fixed-priority scheduler assigns the jobs with the highest priorities to the fastest processors. Since determining whether all tasks can meet their deadlines is generally intractable even with identical processors, we propose two sufficient schedulability tests that calculate upper bounds on the task’s worst-case response time within polynomial and pseudo-polynomial time. The proposed tests leverage the linear programming model to upper bound the interference of the higher-priority tasks. Furthermore, we identify specific conditions and platforms upon which the problem can be solved more efficiently within linear time. These formulations are used to iteratively evaluate and refine possible solutions until a safe upper bound on the task’s worst-case response time is found. Additionally, we demonstrate that, with specific minor modifications, the proposed tests are compatible with Audsley’s optimal priority assignment. Experimental evaluations performed on synthetic task sets show that the proposed approach outperforms the state-of-the-art methods.
Cite as

Binqi Sun, Tomasz Kloda, and Marco Caccamo. Response Time Analysis for Fixed-Priority Preemptive Uniform Multiprocessor Systems. In 36th Euromicro Conference on Real-Time Systems (ECRTS 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 298, pp. 17:1-17:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{sun_et_al:LIPIcs.ECRTS.2024.17,
  author =	{Sun, Binqi and Kloda, Tomasz and Caccamo, Marco},
  title =	{{Response Time Analysis for Fixed-Priority Preemptive Uniform Multiprocessor Systems}},
  booktitle =	{36th Euromicro Conference on Real-Time Systems (ECRTS 2024)},
  pages =	{17:1--17:24},
  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.2024.17},
  URN =		{urn:nbn:de:0030-drops-203201},
  doi =		{10.4230/LIPIcs.ECRTS.2024.17},
  annote =	{Keywords: Real-time scheduling, Uniform multiprocessor, Response time analysis}
}
Document
DOI: 10.4230/LIPIcs.ECRTS.2020.1
Fixed-Priority Memory-Centric Scheduler for COTS-Based Multiprocessors

Authors: Gero Schwäricke, Tomasz Kloda, Giovani Gracioli, Marko Bertogna, and Marco Caccamo

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

Abstract
Memory-centric scheduling attempts to guarantee temporal predictability on commercial-off-the-shelf (COTS) multiprocessor systems to exploit their high performance for real-time applications. Several solutions proposed in the real-time literature have hardware requirements that are not easily satisfied by modern COTS platforms, like hardware support for strict memory partitioning or the presence of scratchpads. However, even without said hardware support, it is possible to design an efficient memory-centric scheduler. In this article, we design, implement, and analyze a memory-centric scheduler for deterministic memory management on COTS multiprocessor platforms without any hardware support. Our approach uses fixed-priority scheduling and proposes a global "memory preemption" scheme to boost real-time schedulability. The proposed scheduling protocol is implemented in the Jailhouse hypervisor and Erika real-time kernel. Measurements of the scheduler overhead demonstrate the applicability of the proposed approach, and schedulability experiments show a 20% gain in terms of schedulability when compared to contention-based and static fair-share approaches.
Cite as

Gero Schwäricke, Tomasz Kloda, Giovani Gracioli, Marko Bertogna, and Marco Caccamo. Fixed-Priority Memory-Centric Scheduler for COTS-Based Multiprocessors. In 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 165, pp. 1:1-1:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{schwaricke_et_al:LIPIcs.ECRTS.2020.1,
  author =	{Schw\"{a}ricke, Gero and Kloda, Tomasz and Gracioli, Giovani and Bertogna, Marko and Caccamo, Marco},
  title =	{{Fixed-Priority Memory-Centric Scheduler for COTS-Based Multiprocessors}},
  booktitle =	{32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)},
  pages =	{1:1--1:24},
  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.2020.1},
  URN =		{urn:nbn:de:0030-drops-123648},
  doi =		{10.4230/LIPIcs.ECRTS.2020.1},
  annote =	{Keywords: Schedulability Analysis, Scheduler Implementation, memory-centric Scheduling, Virtualization, Multiprocessor}
}
Document
DOI: 10.4230/LIPIcs.ECRTS.2019.27
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.
Cite as

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
DOI: 10.4230/LIPIcs.ECRTS.2017.3
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}
}
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