Search Results

Documents authored by Biondi, Alessandro


Document
Optimizing Per-Core Priorities to Minimize End-To-End Latencies

Authors: Francesco Paladino, Alessandro Biondi, Enrico Bini, and Paolo Pazzaglia

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


Abstract
Logical Execution Time (LET) allows decoupling the schedule of real-time periodic tasks from their communication, with the advantage of isolating the communication pattern from the variability of the schedule. However, when such tasks are organized in chains, the usage of LET at the task level does not necessarily transfer the same LET properties to the chain level. In this paper, we extend a LET-like model from tasks to chains spanning over multiple cores. We leverage the designed constant latency chains to optimize per-core priority assignment. Finally, we also provide a set of heuristic algorithms, that are compared in a large-scale experimental evaluation.

Cite as

Francesco Paladino, Alessandro Biondi, Enrico Bini, and Paolo Pazzaglia. Optimizing Per-Core Priorities to Minimize End-To-End Latencies. In 36th Euromicro Conference on Real-Time Systems (ECRTS 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 298, pp. 6:1-6:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)


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@InProceedings{paladino_et_al:LIPIcs.ECRTS.2024.6,
  author =	{Paladino, Francesco and Biondi, Alessandro and Bini, Enrico and Pazzaglia, Paolo},
  title =	{{Optimizing Per-Core Priorities to Minimize End-To-End Latencies}},
  booktitle =	{36th Euromicro Conference on Real-Time Systems (ECRTS 2024)},
  pages =	{6:1--6:25},
  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.2024.6},
  URN =		{urn:nbn:de:0030-drops-203094},
  doi =		{10.4230/LIPIcs.ECRTS.2024.6},
  annote =	{Keywords: Cause-Effect Chains, Logical Execution Time, End-to-End Latency, Design Optimization, Task Priorities, Data Age, Reaction Time}
}
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
Replication-Based Scheduling of Parallel Real-Time Tasks

Authors: Federico Aromolo, Geoffrey Nelissen, and Alessandro Biondi

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


Abstract
Multiprocessors have become the standard computing platform for real-time embedded systems. To efficiently leverage the computational power of such platforms, software tasks are often characterized by an internal structure where concurrent subtasks can execute in parallel on different processors. Existing strategies for the scheduling of parallel real-time tasks on multiprocessor platforms, such as partitioned, global, and federated scheduling, were inspired by earlier techniques that were not conceived to explicitly support parallel tasks, thus carrying advantages but also well-known limitations. This paper introduces replication-based scheduling, a specialized scheduling paradigm for parallel real-time DAG tasks. Replication-based scheduling leverages the internal structure of the parallel tasks to assign replicas of the subtasks to different processors, while ensuring that exactly one replica of each subtask will be executed at runtime for every task instance. This approach aims at preserving the advantages of partitioned scheduling while simplifying the timing analysis. The replication-based scheduling framework is first defined, together with a strategy for implementing replication-based scheduling in real-time operating systems. Then, offline allocation strategies for subtask replicas and a response-time analysis are presented. In the provided experiments, the schedulability achieved with replication-based scheduling is compared with that of existing techniques for the scheduling of parallel real-time tasks on multiprocessors.

Cite as

Federico Aromolo, Geoffrey Nelissen, and Alessandro Biondi. Replication-Based Scheduling of Parallel Real-Time Tasks. In 35th Euromicro Conference on Real-Time Systems (ECRTS 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 262, pp. 18:1-18:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{aromolo_et_al:LIPIcs.ECRTS.2023.18,
  author =	{Aromolo, Federico and Nelissen, Geoffrey and Biondi, Alessandro},
  title =	{{Replication-Based Scheduling of Parallel Real-Time Tasks}},
  booktitle =	{35th Euromicro Conference on Real-Time Systems (ECRTS 2023)},
  pages =	{18:1--18:23},
  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.2023.18},
  URN =		{urn:nbn:de:0030-drops-180477},
  doi =		{10.4230/LIPIcs.ECRTS.2023.18},
  annote =	{Keywords: Real-Time Systems, Scheduling Algorithms, Schedulability Analysis, Parallel Tasks}
}
Document
Artifact
Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling (Artifact)

Authors: Federico Aromolo, Alessandro Biondi, and Geoffrey Nelissen

Published in: DARTS, Volume 8, Issue 1, Special Issue of the 34th Euromicro Conference on Real-Time Systems (ECRTS 2022)


Abstract
This artifact provides the means to validate and reproduce the experimental results presented in the related paper "Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling". The paper introduces a response-time analysis for constrained-deadline self-suspending tasks scheduled under EDF on a uniprocessor system, based on a model transformation from self-suspending sporadic tasks to sporadic tasks with jitter. In the experimental evaluation presented in the paper, the performance of the proposed analysis approach for self-suspending tasks is compared with that of existing suspension-oblivious and suspension-aware analysis techniques.

Cite as

Federico Aromolo, Alessandro Biondi, and Geoffrey Nelissen. Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling (Artifact). In Special Issue of the 34th Euromicro Conference on Real-Time Systems (ECRTS 2022). Dagstuhl Artifacts Series (DARTS), Volume 8, Issue 1, pp. 5:1-5:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@Article{aromolo_et_al:DARTS.8.1.5,
  author =	{Aromolo, Federico and Biondi, Alessandro and Nelissen, Geoffrey},
  title =	{{Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling (Artifact)}},
  pages =	{5:1--5:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2022},
  volume =	{8},
  number =	{1},
  editor =	{Aromolo, Federico and Biondi, Alessandro and Nelissen, Geoffrey},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.8.1.5},
  URN =		{urn:nbn:de:0030-drops-165012},
  doi =		{10.4230/DARTS.8.1.5},
  annote =	{Keywords: Real-Time Systems, Schedulability Analysis, Self-Suspending Tasks, EDF Scheduling}
}
Document
Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling

Authors: Federico Aromolo, Alessandro Biondi, and Geoffrey Nelissen

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


Abstract
The self-suspending task model proved to be particularly effective in capturing the timing behavior of real-time systems characterized by complex execution patterns, such as computation offloading to hardware accelerators, inter-core synchronization by means of multiprocessor locking protocols, and highly parallel computation. Most of the existing results for the timing analysis of self-suspending tasks do not support the widely adopted Earliest Deadline First (EDF) scheduling algorithm, being instead primarily focused on fixed-priority scheduling. This paper presents a response-time analysis for constrained-deadline self-suspending tasks scheduled under EDF on a uniprocessor system. The proposed analysis is based on a model transformation from self-suspending sporadic tasks to sporadic tasks with jitter, which can then be analyzed using a state-of-the-art analysis method for EDF scheduling. Experimental results are presented to compare the performance of the proposed technique in terms of schedulability ratio with that of the pessimistic suspension-oblivious approach and with a less general technique for task sets with implicit deadlines.

Cite as

Federico Aromolo, Alessandro Biondi, and Geoffrey Nelissen. Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling. In 34th Euromicro Conference on Real-Time Systems (ECRTS 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 231, pp. 13:1-13:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{aromolo_et_al:LIPIcs.ECRTS.2022.13,
  author =	{Aromolo, Federico and Biondi, Alessandro and Nelissen, Geoffrey},
  title =	{{Response-Time Analysis for Self-Suspending Tasks Under EDF Scheduling}},
  booktitle =	{34th Euromicro Conference on Real-Time Systems (ECRTS 2022)},
  pages =	{13:1--13:18},
  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.2022.13},
  URN =		{urn:nbn:de:0030-drops-163306},
  doi =		{10.4230/LIPIcs.ECRTS.2022.13},
  annote =	{Keywords: Real-Time Systems, Schedulability Analysis, Self-Suspending Tasks, EDF Scheduling}
}
Document
Front Matter
Front Matter - ECRTS 2021 Artifacts, Table of Contents, Artifact Evaluation Committee

Authors: Alessandro Biondi and Angeliki Kritikakou

Published in: DARTS, Volume 7, Issue 1, Special Issue of the 33rd Euromicro Conference on Real-Time Systems (ECRTS 2021)


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

Cite as

Special Issue of the 33rd Euromicro Conference on Real-Time Systems (ECRTS 2021). Dagstuhl Artifacts Series (DARTS), Volume 7, Issue 1, pp. 0:i-0:x, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


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@Article{biondi_et_al:DARTS.7.1.0,
  author =	{Biondi, Alessandro and Kritikakou, Angeliki},
  title =	{{Front Matter - ECRTS 2021 Artifacts, Table of Contents, Artifact Evaluation Committee}},
  pages =	{0:i--0:x},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2021},
  volume =	{7},
  number =	{1},
  editor =	{Biondi, Alessandro and Kritikakou, Angeliki},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.7.1.0},
  URN =		{urn:nbn:de:0030-drops-139794},
  doi =		{10.4230/DARTS.7.1.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
Scheduling Replica Voting in Fixed-Priority Real-Time Systems

Authors: Pietro Fara, Gabriele Serra, Alessandro Biondi, and Ciro Donnarumma

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


Abstract
Reliability and safety are mandatory requirements for safety-critical embedded systems. The design of a fault-tolerant system is required in many fields (e.g., railway, automotive, avionics) and redundancy helps in achieving this goal. Redundant systems typically leverage voting techniques applied to the outputs produced by tasks to detect and even tolerate failures. This paper studies the integration of distributed voting protocols in fixed-priority real-time systems from a scheduling perspective. It analyzes two scheduling strategies for implementing voting. One is attractive and friendly for software developers and based on suspending the task execution until the replica provides the data to be voted. The other one is inspired by the Logical Execution Time (LET) paradigm and requires introducing additional tasks in the system to accomplish voting-related activities. Queuing and delays introduced by inter-replica communication interfaces are also analyzed. Experimental results are finally presented to compare the two strategies, showing that LET-inspired voting is much more predictable and hence more suitable than the other strategy for fixed-priority real-time systems.

Cite as

Pietro Fara, Gabriele Serra, Alessandro Biondi, and Ciro Donnarumma. Scheduling Replica Voting in Fixed-Priority Real-Time Systems. In 33rd Euromicro Conference on Real-Time Systems (ECRTS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 196, pp. 13:1-13:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


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@InProceedings{fara_et_al:LIPIcs.ECRTS.2021.13,
  author =	{Fara, Pietro and Serra, Gabriele and Biondi, Alessandro and Donnarumma, Ciro},
  title =	{{Scheduling Replica Voting in Fixed-Priority Real-Time Systems}},
  booktitle =	{33rd Euromicro Conference on Real-Time Systems (ECRTS 2021)},
  pages =	{13:1--13:21},
  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.2021.13},
  URN =		{urn:nbn:de:0030-drops-139449},
  doi =		{10.4230/LIPIcs.ECRTS.2021.13},
  annote =	{Keywords: Real-time systems, safety-critical systems, voting, redundancy, fault-tolerance, logical execution time}
}
Document
Front Matter
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Alessandro V. Papadopoulos and Alessandro Biondi

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


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

Cite as

Special Issue of the 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 1, pp. 0:i-0:x, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@Article{papadopoulos_et_al:DARTS.6.1.0,
  author =	{Papadopoulos, Alessandro V. and Biondi, Alessandro},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  pages =	{0:i--0:x},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{1},
  editor =	{Papadopoulos, Alessandro V. and Biondi, Alessandro},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.1.0},
  URN =		{urn:nbn:de:0030-drops-123904},
  doi =		{10.4230/DARTS.6.1.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
Artifact
Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs (Artifact)

Authors: Francesco Restuccia, Marco Pagani, Alessandro Biondi, Mauro Marinoni, and Giorgio Buttazzo

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


Abstract
This artifact provides the means for reproducing the experiments presented in the paper "Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoC". In particular, it provides the means and describes how to replicate the experimental study that has been carried out to evaluate the proposed analysis with synthetic workloads.

Cite as

Francesco Restuccia, Marco Pagani, Alessandro Biondi, Mauro Marinoni, and Giorgio Buttazzo. Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs (Artifact). In Special Issue of the 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 1, pp. 4:1-4:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@Article{restuccia_et_al:DARTS.6.1.4,
  author =	{Restuccia, Francesco and Pagani, Marco and Biondi, Alessandro and Marinoni, Mauro and Buttazzo, Giorgio},
  title =	{{Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs (Artifact)}},
  pages =	{4:1--4:3},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{1},
  editor =	{Restuccia, Francesco and Pagani, Marco and Biondi, Alessandro and Marinoni, Mauro and Buttazzo, Giorgio},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.1.4},
  URN =		{urn:nbn:de:0030-drops-123941},
  doi =		{10.4230/DARTS.6.1.4},
  annote =	{Keywords: Heterogeneous computing, Predictable hardware acceleration, FPGA SoCs, Multi-Master architectures}
}
Document
Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs

Authors: Francesco Restuccia, Marco Pagani, Alessandro Biondi, Mauro Marinoni, and Giorgio Buttazzo

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


Abstract
FPGA System-on-Chips (SoCs) are heterogeneous platforms that combine general-purpose processors with a field-programmable gate array (FPGA) fabric. The FPGA fabric is composed of a programmable logic in which hardware accelerators can be deployed to accelerate the execution of specific functionality. The main source of unpredictability when bounding the execution times of hardware accelerators pertains the access to the shared memories via the on-chip bus. This work is focused on bounding the worst-case bus contention experienced by the hardware accelerators deployed in the FPGA fabric. To this end, this work considers the AMBA AXI bus, which is the de-facto standard communication interface used in most the commercial off-the-shelf (COTS) FPGA SoCs, and presents an analysis technique to bound the response times of hardware accelerators implemented on such platforms. A fine-grained modeling of the AXI bus and AXI interconnects is first provided. Then, contention delays are studied under hierarchical bus infrastructures with arbitrary depths. Experimental results are finally presented to validate the proposed model with execution traces on two modern FPGA-based SoC produced by Xilinx (Zynq-7000 and Zynq-Ultrascale+ families) and to assess the performance of the proposed analysis.

Cite as

Francesco Restuccia, Marco Pagani, Alessandro Biondi, Mauro Marinoni, and Giorgio Buttazzo. Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs. In 32nd Euromicro Conference on Real-Time Systems (ECRTS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 165, pp. 12:1-12:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{restuccia_et_al:LIPIcs.ECRTS.2020.12,
  author =	{Restuccia, Francesco and Pagani, Marco and Biondi, Alessandro and Marinoni, Mauro and Buttazzo, Giorgio},
  title =	{{Modeling and Analysis of Bus Contention for Hardware Accelerators in FPGA SoCs}},
  booktitle =	{32nd Euromicro Conference on Real-Time Systems (ECRTS 2020)},
  pages =	{12:1--12:23},
  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.2020.12},
  URN =		{urn:nbn:de:0030-drops-123753},
  doi =		{10.4230/LIPIcs.ECRTS.2020.12},
  annote =	{Keywords: Heterogeneous computing, Predictable hardware acceleration, FPGA SoCs, Multi-Master architectures}
}
Document
A Bandwidth Reservation Mechanism for AXI-Based Hardware Accelerators on FPGAs

Authors: Marco Pagani, Enrico Rossi, Alessandro Biondi, Mauro Marinoni, Giuseppe Lipari, and Giorgio Buttazzo

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


Abstract
Hardware platforms for real-time embedded systems are evolving towards heterogeneous architectures comprising different types of processing cores and dedicated hardware accelerators, which can be implemented on silicon or dynamically deployed on FPGA fabric. Such accelerators typically access a shared memory to exchange a significant amount of data with other processing elements. Existing COTS solutions focus on maximizing the overall throughput of the system, rather than guaranteeing the timing constraints of individual hardware accelerators. This paper presents the AXI budgeting unit (ABU), a hardware-based solution to implement a bandwidth reservation mechanism on top of the AMBA AXI standard infrastructure for hardware accelerators deployed on FPGAs. An accurate and tractable model, as well as the corresponding analysis, are also proposed to bound the response time of hardware accelerators in the presence of ABUs, in order to verify whether they can complete before their deadlines. Finally, a set of experiments are reported to evaluate the proposed approach on a state-of-the-art platform, namely the Zynq-7020 by Xilinx. The resource consumption of the ABU has been quantified to be less than 1% of the total FPGA resources of the Zynq-7020.

Cite as

Marco Pagani, Enrico Rossi, Alessandro Biondi, Mauro Marinoni, Giuseppe Lipari, and Giorgio Buttazzo. A Bandwidth Reservation Mechanism for AXI-Based Hardware Accelerators on FPGAs. In 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 133, pp. 24:1-24:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{pagani_et_al:LIPIcs.ECRTS.2019.24,
  author =	{Pagani, Marco and Rossi, Enrico and Biondi, Alessandro and Marinoni, Mauro and Lipari, Giuseppe and Buttazzo, Giorgio},
  title =	{{A Bandwidth Reservation Mechanism for AXI-Based Hardware Accelerators on FPGAs}},
  booktitle =	{31st Euromicro Conference on Real-Time Systems (ECRTS 2019)},
  pages =	{24:1--24:24},
  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.2019.24},
  URN =		{urn:nbn:de:0030-drops-107611},
  doi =		{10.4230/LIPIcs.ECRTS.2019.24},
  annote =	{Keywords: AXI Bus, Bandwidth Reservation, Hardware Acceleration, FPGA}
}
Document
Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses

Authors: Paolo Pazzaglia, Luigi Pannocchi, Alessandro Biondi, and Marco Di Natale

Published in: LIPIcs, Volume 106, 30th Euromicro Conference on Real-Time Systems (ECRTS 2018)


Abstract
Most works in schedulability analysis theory are based on the assumption that constraints on the performance of the application can be expressed by a very limited set of timing constraints (often simply hard deadlines) on a task model. This model is insufficient to represent a large number of systems in which deadlines can be missed, or in which late task responses affect the performance, but not the correctness of the application. For systems with a possible temporary overload, models like the m-K deadline have been proposed in the past. However, the m-K model has several limitations since it does not consider the state of the system and is largely unaware of the way in which the performance is affected by deadline misses (except for critical failures). In this paper, we present a state-based representation of the evolution of a system with respect to each deadline hit or miss event. Our representation is much more general (while hopefully concise enough) to represent the evolution in time of the performance of time-sensitive systems with possible time overloads. We provide the theoretical foundations for our model and also show an application to a simple system to give examples of the state representations and their use.

Cite as

Paolo Pazzaglia, Luigi Pannocchi, Alessandro Biondi, and Marco Di Natale. Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses. In 30th Euromicro Conference on Real-Time Systems (ECRTS 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 106, pp. 10:1-10:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{pazzaglia_et_al:LIPIcs.ECRTS.2018.10,
  author =	{Pazzaglia, Paolo and Pannocchi, Luigi and Biondi, Alessandro and Di Natale, Marco},
  title =	{{Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses}},
  booktitle =	{30th Euromicro Conference on Real-Time Systems (ECRTS 2018)},
  pages =	{10:1--10:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-075-0},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{106},
  editor =	{Altmeyer, Sebastian},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2018.10},
  URN =		{urn:nbn:de:0030-drops-89930},
  doi =		{10.4230/LIPIcs.ECRTS.2018.10},
  annote =	{Keywords: control, real-time, cyber physical systems, weakly hard, deadline miss, performance}
}
Document
Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses (Artifact)

Authors: Paolo Pazzaglia, Luigi Pannocchi, Alessandro Biondi, and Marco Di Natale

Published in: DARTS, Volume 4, Issue 2, Special Issue of the 30th Euromicro Conference on Real-Time Systems (ECRTS 2018)


Abstract
This document provides a brief description of the artifact material related to the paper "Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses". The code provided in the artifact implements the algorithms presented in the paper and all the experimental tests.

Cite as

Paolo Pazzaglia, Luigi Pannocchi, Alessandro Biondi, and Marco Di Natale. Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses (Artifact). In Special Issue of the 30th Euromicro Conference on Real-Time Systems (ECRTS 2018). Dagstuhl Artifacts Series (DARTS), Volume 4, Issue 2, pp. 4:1-4:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@Article{pazzaglia_et_al:DARTS.4.2.4,
  author =	{Pazzaglia, Paolo and Pannocchi, Luigi and Biondi, Alessandro and Di Natale, Marco},
  title =	{{Beyond the Weakly Hard Model: Measuring the Performance Cost of Deadline Misses (Artifact)}},
  pages =	{4:1--4:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2018},
  volume =	{4},
  number =	{2},
  editor =	{Pazzaglia, Paolo and Pannocchi, Luigi and Biondi, Alessandro and Di Natale, Marco},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.4.2.4},
  URN =		{urn:nbn:de:0030-drops-89728},
  doi =		{10.4230/DARTS.4.2.4},
  annote =	{Keywords: control, real-time, Cyber Physical Systems weakly hard, deadline miss, performance}
}
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}
}
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