Data dependent energy modelling for worst case energy consumption analysis

Safely meeting Worst Case Energy Consumption (WCEC) criteria requires accurate energy modeling of software. We investigate the impact of instruction operand values upon energy consumption in cacheless embedded processors. Existing instruction-level energy models typically use measurements from random input data, providing estimates unsuitable for safe WCEC analysis. We examine probabilistic energy distributions of instructions and propose a model for composing instruction sequences using distributions, enabling WCEC analysis on program basic blocks. The worst case is predicted with statistical analysis. Further, we verify that the energy of embedded benchmarks can be characterised as a distribution, and compare our proposed technique with other methods of estimating energy consumption

Methoden zur applikationsspezifischen Verlustleitungsoptimierung für eingebettete Prozessoren

Dieser Beitrag beschreibt eine Methodik zur Verlustleistungsmodellierung von eingebetteten Prozessoren im Entwurfsstadium auf Basis der Hardwarebeschreibung. Die Methodik wurde exemplarisch auf einen typischen RISC-Prozessor angewendet. Die gewonnenen Verlustleistungsmodelle zeigen eine geringe Abweichung hinsichtlich der mittleren Verlustleistungsaufnahme von unter 5% und eine hohe Güte bezüglich des zeitlichen Verlaufes der Verlustleistungsaufnahme im Vergleich zur sehr zeitaufwendigen Simulation der Gatter-Netzliste. Zudem lassen sich die Modelle zusammen mit der funktionalen Emulation des Prozessors auf einem FPGA abbilden. Die hohe Ausführungsgeschwindigkeit der Emulation erlaubt sowohl eine umfassende, verlustleistungsorientierte Optimierung der Anwendungen durch den Applikationsentwickler als auch eine anwendungsorientierte Optimierung der Prozessorarchitektur durch den Hardwareentwickler

System-Level Energy-Aware Design of Cyber-Physical Systems

In this technical report we present the work conducted during the first part of the PhD thesis “System-Level Energy-Aware Design of Cyber-Physical Systems”. We present the application of modelling techniques and methodologies to study energy consumption during the design and implementation of cyber-physical systems. This study is made from the electro-mechanical and computation angle. Additionally we present a setup that allows the combination of abstract models with hardware and software preliminary realizations. This allows a stepwise model to implementation transformation and improved model accuracy. Some of these techniques have been applied to the case study e-Stocking and others have been studied with more simple experimental setups.In addition to the scientific content, we also present a description of the envisioned future work and the plans that will lead to completion of this PhD thesis by April 2015

Energy-Aware System-Level Design of Cyber-Physical Systems

Cyber-Physical Systems (CPSs) are heterogeneous systems in which one or several computational cores interact with the physical environment. This interaction is typically performed through electromechanical elements such as sensors and actuators. Many CPSs operate as part of a network and some of them present a constrained energy budget (for example, they are battery powered). Examples of energy constrained CPSs could be a mobile robot, the nodes that compose a Body Area Network or a pacemaker. The heterogeneity present in the composition of CPSs together with the constrained energy availability makes these systems challenging to design. A way to tackle both complexity and costs is the application of abstract modelling and simulation. This thesis proposed the application of modelling at the system level, taking energy consumption in the different kinds of subsystems into consideration. By adopting this cross disciplinary approach to energy consumption it is possible to decrease it effectively. The results of this thesis are a number of modelling guidelines and tool improvements to support this kind of holistic analysis, covering energy consumption in electromechanical, computation and communication subsystems. From a methodological point of view these have been framed within a V-lifecycle. Finally, this approach has been demonstrated on two case studies from the medical domain enabling the exploration of alternative systems architectures and producing energy consumption estimates to conduct trade-off analysis