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Documents authored by Casini, Daniel


Document
Bounding the Data-Delivery Latency of DDS Messages in Real-Time Applications

Authors: Gerlando Sciangula, Daniel Casini, Alessandro Biondi, Claudio Scordino, and Marco Di Natale

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


Abstract
Many modern applications need to run on massively interconnected sets of heterogeneous nodes, ranging from IoT devices to edge nodes up to the Cloud. In this scenario, communication is often implemented using the publish-subscribe paradigm. The Data Distribution Service (DDS) is a popular middleware specification adopting such a paradigm. The DDS is becoming a key enabler for massively distributed real-time applications, with popular frameworks such as ROS 2 and AUTOSAR Adaptive building on it. However, no formal modeling and analysis of the timing properties of DDS has been provided to date. This paper fills this gap by providing an abstract model for DDS systems that can be generalized to any implementation compliant with the specification. A concrete instance of the generic DDS model is provided for the case of eProsima’s FastDDS, which is eventually used to provide a real-time analysis that bounds the data-delivery latency of DDS messages. Finally, this paper reports on an evaluation based on a representative automotive application from the WATERS 2019 challenge by Bosch.

Cite as

Gerlando Sciangula, Daniel Casini, Alessandro Biondi, Claudio Scordino, and Marco Di Natale. Bounding the Data-Delivery Latency of DDS Messages in Real-Time Applications. In 35th Euromicro Conference on Real-Time Systems (ECRTS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 262, pp. 9:1-9:26, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{sciangula_et_al:LIPIcs.ECRTS.2023.9,
  author =	{Sciangula, Gerlando and Casini, Daniel and Biondi, Alessandro and Scordino, Claudio and Di Natale, Marco},
  title =	{{Bounding the Data-Delivery Latency of DDS Messages in Real-Time Applications}},
  booktitle =	{35th Euromicro Conference on Real-Time Systems (ECRTS 2023)},
  pages =	{9:1--9:26},
  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.2023.9},
  URN =		{urn:nbn:de:0030-drops-180381},
  doi =		{10.4230/LIPIcs.ECRTS.2023.9},
  annote =	{Keywords: DDS, real-time systems, response-time analysis, end-to-end latency, CPA}
}
Document
Artifact
Demystifying the Real-Time Linux Scheduling Latency (Artifact)

Authors: Daniel Bristot de Oliveira, Daniel Casini, Rômulo Silva de Oliveira, and Tommaso Cucinotta

Published in: DARTS, Volume 6, Issue 1, Special Issue of the 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)


Abstract
The "Demystifying the Real-Time Linux Scheduling Latency" paper defines a safe bound for the real-time Linux scheduling latency. It also presents a tool kit that enables the measurements and analysis of the variables that compose the bond. The tool kit is used in the experimental section, performing the scheduling latency analyses on real platforms. This artifact provides the means to evaluate the tool kit and to reproduce the results of the experimental section.

Cite as

Daniel Bristot de Oliveira, Daniel Casini, Rômulo Silva de Oliveira, and Tommaso Cucinotta. Demystifying the Real-Time Linux Scheduling Latency (Artifact). In Special Issue of the 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 1, pp. 2:1-2:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@Article{deoliveira_et_al:DARTS.6.1.2,
  author =	{de Oliveira, Daniel Bristot and Casini, Daniel and de Oliveira, R\^{o}mulo Silva and Cucinotta, Tommaso},
  title =	{{Demystifying the Real-Time Linux Scheduling Latency (Artifact)}},
  pages =	{2:1--2:3},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{1},
  editor =	{de Oliveira, Daniel Bristot and Casini, Daniel and de Oliveira, R\^{o}mulo Silva and Cucinotta, Tommaso},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.1.2},
  URN =		{urn:nbn:de:0030-drops-123928},
  doi =		{10.4230/DARTS.6.1.2},
  annote =	{Keywords: Real-time operating systems, Linux kernel, PREEMPT\underlineRT, Scheduling latency}
}
Document
Demystifying the Real-Time Linux Scheduling Latency

Authors: Daniel Bristot de Oliveira, Daniel Casini, Rômulo Silva de Oliveira, and Tommaso Cucinotta

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


Abstract
Linux has become a viable operating system for many real-time workloads. However, the black-box approach adopted by cyclictest, the tool used to evaluate the main real-time metric of the kernel, the scheduling latency, along with the absence of a theoretically-sound description of the in-kernel behavior, sheds some doubts about Linux meriting the real-time adjective. Aiming at clarifying the PREEMPT_RT Linux scheduling latency, this paper leverages the Thread Synchronization Model of Linux to derive a set of properties and rules defining the Linux kernel behavior from a scheduling perspective. These rules are then leveraged to derive a sound bound to the scheduling latency, considering all the sources of delays occurring in all possible sequences of synchronization events in the kernel. This paper also presents a tracing method, efficient in time and memory overheads, to observe the kernel events needed to define the variables used in the analysis. This results in an easy-to-use tool for deriving reliable scheduling latency bounds that can be used in practice. Finally, an experimental analysis compares the cyclictest and the proposed tool, showing that the proposed method can find sound bounds faster with acceptable overheads.

Cite as

Daniel Bristot de Oliveira, Daniel Casini, Rômulo Silva de Oliveira, and Tommaso Cucinotta. Demystifying the Real-Time Linux Scheduling Latency. In 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 165, pp. 9:1-9:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{deoliveira_et_al:LIPIcs.ECRTS.2020.9,
  author =	{de Oliveira, Daniel Bristot and Casini, Daniel and de Oliveira, R\^{o}mulo Silva and Cucinotta, Tommaso},
  title =	{{Demystifying the Real-Time Linux Scheduling Latency}},
  booktitle =	{32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)},
  pages =	{9:1--9:23},
  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.2020.9},
  URN =		{urn:nbn:de:0030-drops-123721},
  doi =		{10.4230/LIPIcs.ECRTS.2020.9},
  annote =	{Keywords: Real-time operating systems, Linux kernel, PREEMPT\underlineRT, Scheduling latency}
}
Document
Artifact
Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling (Artifact)

Authors: Daniel Casini, Tobias Blaß, Ingo Lütkebohle, and Björn B. Brandenburg

Published in: DARTS, Volume 5, Issue 1, Special Issue of the 31st Euromicro Conference on Real-Time Systems (ECRTS 2019)


Abstract
This artifact provides the means to validate and reproduce the results of the associated paper "Response-Time Analysis of ROS 2 Processing Chains under Reservation-Based Scheduling." It consists of two independent components. First, it contains a model validation component that validates the paper’s claims about the ROS 2 executor’s callback scheduling. Second, it contains the source code for the paper’s case study, i.e., an implementation of the proposed response-time analysis and a model of the move_base navigation stack.

Cite as

Daniel Casini, Tobias Blaß, Ingo Lütkebohle, and Björn B. Brandenburg. Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling (Artifact). In Special Issue of the 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Dagstuhl Artifacts Series (DARTS), Volume 5, Issue 1, pp. 5:1-5:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@Article{casini_et_al:DARTS.5.1.5,
  author =	{Casini, Daniel and Bla{\ss}, Tobias and L\"{u}tkebohle, Ingo and Brandenburg, Bj\"{o}rn B.},
  title =	{{Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling}},
  pages =	{5:1--5:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2019},
  volume =	{5},
  number =	{1},
  editor =	{Casini, Daniel and Bla{\ss}, Tobias and L\"{u}tkebohle, Ingo and 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/DARTS.5.1.5},
  URN =		{urn:nbn:de:0030-drops-107330},
  doi =		{10.4230/DARTS.5.1.5},
  annote =	{Keywords: ROS, real-time systems, response-time analysis, robotics, resource reservation}
}
Document
Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling

Authors: Daniel Casini, Tobias Blaß, Ingo Lütkebohle, and Björn B. Brandenburg

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


Abstract
Bounding the end-to-end latency of processing chains in distributed real-time systems is a well-studied problem, relevant in multiple industrial fields, such as automotive systems and robotics. Nonetheless, to date, only little attention has been given to the study of the impact that specific frameworks and implementation choices have on real-time performance. This paper proposes a scheduling model and a response-time analysis for ROS 2 (specifically, version "Crystal Clemmys" released in December 2018), a popular framework for the rapid prototyping, development, and deployment of robotics applications with thousands of professional users around the world. The purpose of this paper is threefold. Firstly, it is aimed at providing to robotic engineers a practical analysis to bound the worst-case response times of their applications. Secondly, it shines a light on current ROS 2 implementation choices from a real-time perspective. Finally, it presents a realistic real-time scheduling model, which provides an opportunity for future impact on the robotics industry.

Cite as

Daniel Casini, Tobias Blaß, Ingo Lütkebohle, and Björn B. Brandenburg. Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling. In 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 133, pp. 6:1-6:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{casini_et_al:LIPIcs.ECRTS.2019.6,
  author =	{Casini, Daniel and Bla{\ss}, Tobias and L\"{u}tkebohle, Ingo and Brandenburg, Bj\"{o}rn B.},
  title =	{{Response-Time Analysis of ROS 2 Processing Chains Under Reservation-Based Scheduling}},
  booktitle =	{31st Euromicro Conference on Real-Time Systems (ECRTS 2019)},
  pages =	{6:1--6:23},
  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.2019.6},
  URN =		{urn:nbn:de:0030-drops-107431},
  doi =		{10.4230/LIPIcs.ECRTS.2019.6},
  annote =	{Keywords: ROS, real-time systems, response-time analysis, robotics, resource reservation}
}
Document
Semi-Partitioned Scheduling of Dynamic Real-Time Workload: A Practical Approach Based on Analysis-Driven Load Balancing

Authors: Daniel Casini, Alessandro Biondi, and Giorgio Buttazzo

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


Abstract
Recent work showed that semi-partitioned scheduling can achieve near-optimal schedulability performance, is simpler to implement compared to global scheduling, and less heavier in terms of runtime overhead, thus resulting in an excellent choice for implementing real-world systems. However, semi-partitioned scheduling typically leverages an off-line design to allocate tasks across the available processors, which requires a-priori knowledge of the workload. Conversely, several simple global schedulers, as global earliest-deadline first (G-EDF), can transparently support dynamic workload without requiring a task-allocation phase. Nonetheless, such schedulers exhibit poor worst-case performance. This work proposes a semi-partitioned approach to efficiently schedule dynamic real-time workload on a multiprocessor system. A linear-time approximation for the C=D splitting scheme under partitioned EDF scheduling is first presented to reduce the complexity of online scheduling decisions. Then, a load-balancing algorithm is proposed for admitting new real-time workload in the system with limited workload re-allocation. A large-scale experimental study shows that the linear-time approximation has a very limited utilization loss compared to the exact technique and the proposed approach achieves very high schedulability performance, with a consistent improvement on G-EDF and pure partitioned EDF scheduling.

Cite as

Daniel Casini, Alessandro Biondi, and Giorgio Buttazzo. Semi-Partitioned Scheduling of Dynamic Real-Time Workload: A Practical Approach Based on Analysis-Driven Load Balancing. In 29th Euromicro Conference on Real-Time Systems (ECRTS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 76, pp. 13:1-13:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{casini_et_al:LIPIcs.ECRTS.2017.13,
  author =	{Casini, Daniel and Biondi, Alessandro and Buttazzo, Giorgio},
  title =	{{Semi-Partitioned Scheduling of Dynamic Real-Time Workload: A Practical Approach Based on Analysis-Driven Load Balancing}},
  booktitle =	{29th Euromicro Conference on Real-Time Systems (ECRTS 2017)},
  pages =	{13:1--13:23},
  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.2017.13},
  URN =		{urn:nbn:de:0030-drops-71659},
  doi =		{10.4230/LIPIcs.ECRTS.2017.13},
  annote =	{Keywords: Semi-partitioned scheduling, dynamic workload, real-time}
}