5.7 Schedulability Analysis

Time	Label	Presentation Title Authors
08:30	5.7.1	BOUNDING DEADLINE MISSES IN WEAKLY-HARD REAL-TIME SYSTEMS WITH TASK DEPENDENCIES Speaker: Zain A. H. Hammadeh, TU Braunschweig, DE Authors: Zain A. H. Hammadeh¹, Sophie Quinton², Rolf Ernst¹, Rafik Henia³ and Laurent Rioux³ ¹TU Braunschweig, DE; ²Inria, FR; ³Thales Research & Technology, FR Abstract Real-time systems with functional dependencies between tasks often require end-to-end (as opposed to task-level) guarantees. For many of these systems, it is even possible to accept the possibility of longer end-to-end delays if one can bound their frequency. Such systems are called weakly-hard. In this paper we provide end-to-end deadline miss models for systems with task chains using Typical Worst-Case Analysis(TWCA). This bounds the number of potential deadline misses in a given sequence of activations of a task chain. To achieve this we exploit task chain properties which arise from the priority assignment of tasks in static-priority preemptive systems. This work is motivated by and validated on a realistic case study inspired by industrial practice and synthetic test cases. Download Paper (PDF; Only available from the DATE venue WiFi)
09:00	5.7.2	REAL-TIME COMMUNICATION ANALYSIS FOR NETWORKS-ON-CHIP WITH BACKPRESSURE Speaker: Sebastian Tobuschat, TU Braunschweig, DE Authors: Sebastian Tobuschat and Rolf Ernst, TU Braunschweig, DE Abstract Networks-on-Chip (NoCs) for safety-critical domains require formal guarantees for the worst-case behavior of all real-time senders. The majority of existing analysis approaches is capable of providing such guarantees only under the assumption that the queues in the routers never overflow, i.e., that no backpressure occurs. This leads to overly pessimistic guarantees or unfulfilled design requirements in many setups using commercially available NoCs where buffer space is limited. Therefore, we propose an alternative analysis methodology providing formal timing guarantees for packet latencies also in a NoC where backpressure occurs. The analysis allows exploiting the behavior of individual traffic streams to determine safe upper bounds on the latency of individual packets. The correctness of the analysis is evaluated experimentally through comparison with simulation results. Download Paper (PDF; Only available from the DATE venue WiFi)
09:30	5.7.3	PROBABILISTIC SCHEDULABILITY ANALYSIS FOR FIXED PRIORITY MIXED CRITICALITY REAL-TIME SYSTEMS Speaker: Yasmina Abdeddaïm, Université Paris-Est, LIGM, ESIEE Paris, FR Authors: Yasmina Abdeddaim¹ and Dorin Maxim² ¹Université Paris-Est, LIGM, ESIEE-Paris, FR; ²University of Lorraine - Loria - Inria Nancy Grand Est, FR Abstract In this paper we present a probabilistic response time analysis for mixed criticality real-time systems running on a single processor according to a fixed priority pre-emptive scheduling policy. The analysis extends the existing state of the art probabilistic analysis to the case of mixed criticalities, taking into account both the level of assurance at which each task needs to be certified, as well as the possible criticalities at which the system may execute. The proposed analysis is formally presented as well as explained with the aid of an illustrative example. Download Paper (PDF; Only available from the DATE venue WiFi)
10:00		End of session Coffee Break in Exhibition Area On all conference days (Tuesday to Thursday), coffee and tea will be served during the coffee breaks at the below-mentioned times in the exhibition area. Tuesday, March 28, 2017 Coffee Break 10:30 - 11:30 Coffee Break 16:00 - 17:00 Wednesday, March 29, 2017 Coffee Break 10:00 - 11:00 Coffee Break 16:00 - 17:00 Thursday, March 30, 2017 Coffee Break 10:00 - 11:00 Coffee Break 15:30 - 16:00

Time

Label

Presentation Title
Authors

08:30

5.7.1

BOUNDING DEADLINE MISSES IN WEAKLY-HARD REAL-TIME SYSTEMS WITH TASK DEPENDENCIES
Speaker:
Zain A. H. Hammadeh, TU Braunschweig, DE
Authors:
Zain A. H. Hammadeh¹, Sophie Quinton², Rolf Ernst¹, Rafik Henia³ and Laurent Rioux³
¹TU Braunschweig, DE; ²Inria, FR; ³Thales Research & Technology, FR
Abstract
Real-time systems with functional dependencies between tasks often require end-to-end (as opposed to task-level) guarantees. For many of these systems, it is even possible to accept the possibility of longer end-to-end delays if one can bound their frequency. Such systems are called weakly-hard. In this paper we provide end-to-end deadline miss models for systems with task chains using Typical Worst-Case Analysis(TWCA). This bounds the number of potential deadline misses in a given sequence of activations of a task chain. To achieve this we exploit task chain properties which arise from the priority assignment of tasks in static-priority preemptive systems. This work is motivated by and validated on a realistic case study inspired by industrial practice and synthetic test cases.
Download Paper (PDF; Only available from the DATE venue WiFi)

09:00

5.7.2

REAL-TIME COMMUNICATION ANALYSIS FOR NETWORKS-ON-CHIP WITH BACKPRESSURE
Speaker:
Sebastian Tobuschat, TU Braunschweig, DE
Authors:
Sebastian Tobuschat and Rolf Ernst, TU Braunschweig, DE
Abstract
Networks-on-Chip (NoCs) for safety-critical domains require formal guarantees for the worst-case behavior of all real-time senders. The majority of existing analysis approaches is capable of providing such guarantees only under the assumption that the queues in the routers never overflow, i.e., that no backpressure occurs. This leads to overly pessimistic guarantees or unfulfilled design requirements in many setups using commercially available NoCs where buffer space is limited. Therefore, we propose an alternative analysis methodology providing formal timing guarantees for packet latencies also in a NoC where backpressure occurs. The analysis allows exploiting the behavior of individual traffic streams to determine safe upper bounds on the latency of individual packets. The correctness of the analysis is evaluated experimentally through comparison with simulation results.
Download Paper (PDF; Only available from the DATE venue WiFi)

09:30

5.7.3

PROBABILISTIC SCHEDULABILITY ANALYSIS FOR FIXED PRIORITY MIXED CRITICALITY REAL-TIME SYSTEMS
Speaker:
Yasmina Abdeddaïm, Université Paris-Est, LIGM, ESIEE Paris, FR
Authors:
Yasmina Abdeddaim¹ and Dorin Maxim²
¹Université Paris-Est, LIGM, ESIEE-Paris, FR; ²University of Lorraine - Loria - Inria Nancy Grand Est, FR
Abstract
In this paper we present a probabilistic response time analysis for mixed criticality real-time systems running on a single processor according to a fixed priority pre-emptive scheduling policy. The analysis extends the existing state of the art probabilistic analysis to the case of mixed criticalities, taking into account both the level of assurance at which each task needs to be certified, as well as the possible criticalities at which the system may execute. The proposed analysis is formally presented as well as explained with the aid of an illustrative example.
Download Paper (PDF; Only available from the DATE venue WiFi)

10:00

End of session
Coffee Break in Exhibition Area

On all conference days (Tuesday to Thursday), coffee and tea will be served during the coffee breaks at the below-mentioned times in the exhibition area.

Tuesday, March 28, 2017