Energy Management, Bus Contention, and Operating Modes in Multicore based Real-Time Systems


Stefan M. Petters, CISTER Research Unit, IPP


Multicore processors have become a central pillar in real-time embedded systems. In the last ten years this was mainly confined to academic work, but now industrial adoption is in full steam. This is underpinned by activities like the Artemis RECOMP project, which aims to reduce the cost of certification for multicore based systems with mixed criticality workload. the latter describes a mix of critical and uncritical applications in a single device. Within this talk, I will present current activities and results at the CISTER research unit at the Engineering School of the Polytechnic Institute of Porto discussing various angles of such systems. Energy Management in this context relates to the use of dynamic frequency and voltage switching, as well as dynamic use of sleep states. One particular problem in the deployment of multicores is the access to main memory which is ultimately subject to contention by the different cores. Analytical models to bound the impact of the bus activity of applications running on other cores are key to guarantee real-time behaviour. Finally many such systems are subject to different operating modes. An illustrative example are planes, which require different sets of task to execute taxiing, starting, landing and in cruise mode.


Dr. Stefan M. Petters is an alumnus of the Institute of Real-Time Computing Systems at the Technical University of Munich. He received his Dipl.-Ing. degree in 1995 from TUM with a Diplomarbeit in the area of Task-Allocation in Distributed Real-Time Systems using evolutionary algorithms. In 2002 he received the Dr.-Ing. in 2002 with his thesis of ''Worst Case Execution Time Estimation for Advanced Processor Architectures'' under the supervision of Prof. Gerorg Färber. Since completing his degree, he has worked in various prominent research groups. This covers the Real-Time systems group at the University of York, UK, where he continued his work on WCET analysis. In 2004 Stefan moved to the ERTOS group at NICTA, in Sydney Australia. The group his world leading in the operating systems area and he worked in the group on WCET analysis of microkernels, as well as power management of embedded platforms. In 2009 Stefan moved to the CISTER research unit at the Polytechnic Institute of Porto, where he acts as vice-director of the unit and research-line leader for adaptive real-time systems. He continues his work on power management, and low level timing analysis in open real-time systems.