A systematic approach to exploring embedded system architectures at multiple abstraction levels

The sheer complexity of today's embedded systems forces designers to start with modeling and simulating system components and their interactions in the very early design stages. It is therefore imperative to have good tools for exploring a wide range of design choices, especially during the early design stages, where the design space is at its largest. This paper presents an overview of the Sesame framework, which provides high-level modeling and simulation methods and tools for system-level performance evaluation and exploration of heterogeneous embedded systems. More specifically, we describe Sesame's modeling methodology and trajectory. It takes a designer systematically along the path from selecting candidate architectures, using analytical modeling and multiobjective optimization, to simulating these candidate architectures with our system-level simulation environment. This simulation environment subsequently allows for architectural exploration at different levels of abstraction while maintaining high-level and architecture-independent application specifications. We illustrate all these aspects using a case study in which we traverse Sesame's exploration trajectory for a motion-JPEG encoder application.

1 Introduction

Advances in chip technology according to Moore's Law, allowing more and more functionality to be integrated on a single chip, have led to the emergence of Systems on Chip (SoCs). These SoCs are nowadays key to the development of advanced embedded computing systems, such as set-top boxes, digital televisions, and 3G cell phones. Designers of these SoC-based embedded systems are typically faced with conflicting design requirements regarding performance, flexibility, power consumption, and cost. As a result, SoC-based embedded systems often have a heterogeneous system architecture, consisting of components that range from fully programmable processor cores to fully dedicated hardware blocks. Programmable processor technology is used for realizing flexibility, for example, to support multiple applications and future extensions, while dedicated hardware is used to optimize designs in time-critical areas and for power and cost minimization.