Date: Thursday 17 March 2016
Time: 08:30 - 10:00
Location / Room: Konferenz 4

Chair:
Frank Slomka, Universität Ulm, DE

Co-Chair:
Kai Lampka, Uppsala University, SE

The papers in this session introduce new scheduling algorithms and schedulability analyses for modern real-time systems, including systems with parallel and self-suspending tasks, and memory-constrained systems.

Time	Label	Presentation Title Authors
08:30	9.6.1	RESPONSE-TIME ANALYSIS OF DAG TASKS UNDER FIXED PRIORITY SCHEDULING WITH LIMITED PREEMPTIONS Speaker: Maria A. Serrano, Barcelona Supercomputing Center and Technical University of Catalonia, ES Authors: Maria A. Serrano1, Alessandra Melani2, Marko Bertogna3 and Eduardo Quinones4 1Barcelona Supercomputing Center and Technical University of Catalonia, ES; 2Scuola Superiore Sant'Anna, IT; 3University of Modena, IT; 4Barcelona Supercomputing Center, ES Abstract Limited preemptive (LP) scheduling has been demonstrated to effectively improve the schedulability of fully preemptive (FP) and fully non-preemptive (FNP) paradigms. On one side, LP reduces the preemption related overheads of FP; on the other side, it restricts the blocking effects of FNP. However, LP has been applied to multi-core scenarios only when completely sequential task systems are considered. This paper extends the current state-of-the-art response time analysis for global fixed priority scheduling with fixed preemption points by deriving a new response time analysis for DAG-based task-sets. Download Paper (PDF; Only available from the DATE venue WiFi)
09:00	9.6.2	SPEED OPTIMIZATION FOR TASKS WITH TWO RESOURCES Speaker: Alessandra Melani, Scuola Superiore Sant'Anna, IT Authors: Alessandra Melani1, Renato Mancuso2, Daniel Cullina2, Marco Caccamo2 and Lothar Thiele3 1Scuola Superiore Sant'Anna, IT; 2University of Illinois at Urbana-Champaign, US; 3Swiss Federal Institute of Technology (ETH), CH Abstract Multiple resource co-scheduling algorithms and pipelined execution models are becoming increasingly popular, as they better capture the heterogeneous nature of modern architectures. The problem of scheduling tasks composed of multiple stages tied to different resources goes under the name of "flow-shop scheduling". This problem, studied since the '50s to optimize production plants, is known to be NP-hard in the general case. In this paper, we consider a specific instance of the flow-shop task model that captures the behavior of a two-resource (DMA- CPU) system. In this setting, we study the problem of selecting the optimal operating speed of either resource with the goal of minimizing power consumption while meeting schedulability constraints. We derive an algorithm that finds an exact solution to the problem in polynomial time, hence it is suitable for online operation even in the presence of variable real-time workload. Download Paper (PDF; Only available from the DATE venue WiFi)
09:30	9.6.3	SELF-SUSPENSION REAL-TIME TASKS UNDER FIXED-RELATIVE-DEADLINE FIXED-PRIORITY SCHEDULING Speaker: Wen-Hung Huang, TU Dortmund, DE Authors: Wen-Hung Huang and Jian-Jia Chen, TU Dortmund, DE Abstract Selfhyp{}suspension is becoming a prominent characteristic in real-time systems such as: (i) I/O-intensive systems (ii) multi-core processors, and (iii) computation offloading systems with coprocessors, like Graphics Processing Units (GPUs). In this work, we study self-suspension systems under fixed-priority (FP) fixed-relative-deadline (FRD) algorithm by using release enforcement to control self-suspension tasks' behavior. Specifically, we use equal-deadline assignment (EDA) to assign the release phases of computations and suspensions. We provide analysis for deriving the speedup factor of the FP FRD scheduler using suspension-laxity-monotonic (SLM) priority assignment. This is the first positive result to provide bounded speedup factor guarantees for general multi-segment self-suspending task systems. Download Paper (PDF; Only available from the DATE venue WiFi)
10:00		End of session Coffee Break in Exhibition Area