Ed F. Deprettere

System Design Using Kahn Process Networks: The Compaan/Laura Approach

New emerging embedded system platforms in the realm of high-throughput multimedia, imaging, and signal processing will consist of multiple microprocessors and reconfigurable components. One of the major problems is how to program these platforms in a systematic and automated way so as to satisfy the performance need of applications executed on these platforms. In this paper, we present our system design approach as an efficient solution to this programming problem. We show how for an application written in Matlab, a Kahn process network specification can automatically be derived and systematically mapped onto a target platform composed of a microprocessor and an FPGA. Furthermore, we illustrate how the mapping approach is applied on a real-life example, namely an M-JPEG encoder.

Compaan: deriving process networks from Matlab for embedded signal processing architectures

This paper presents the Compaan tool that automatically transforms a nested loop program written in Matlab into a process network specification. The process network model of computation fits better with the new emerging kind of embedded architectures that use coprocessors. Process networks can describe both fine-grained and coarse-grained parallelism, making the mapping of the applications easier.

Systematic and Automated Multiprocessor System Design, Programming, and Implementation

For modern embedded systems in the realm of high-throughput multimedia, imaging, and signal processing, the complexity of embedded applications has reached a point where the performance requirements of these applications can no longer be supported by embedded system architectures based on a single processor. Thus, the emerging embedded system-on-chip platforms are increasingly becoming multiprocessor architectures. As a consequence, two major problems emerge, namely how to design and how to program such multiprocessor platforms in a systematic and automated way in order to reduce the design time and to satisfy the performance needs of applications executed on such platforms. As an efficient solution to these two problems, in this paper, we present the methodology and techniques implemented in a tool called Embedded System-level Platform synthesis and Application Mapping (ESPAM) for automated multiprocessor system design, programming, and implementation. ESPAM moves the design specification and programming from the Register Transfer Level and low-level C to a higher system level of abstraction. We explain how, starting from system-level platform, application, and mapping specifications, a multiprocessor platform is synthesized, programmed, and implemented in a systematic and automated way. The class of multiprocessor platforms we consider is introduced as well. To validate and evaluate our methodology, we used ESPAM to automatically generate and program several multiprocessor systems that execute three image processing applications, namely Sobel edge detection, Discrete Wavelet Transform, and Motion JPEG encoder. The performance of the systems that execute these applications is also presented in this paper.

A framework for rapid system-level exploration, synthesis, and programming of multimedia MP-SoCs

In this paper, we present the Daedalus framework, which allows for traversing the path from sequential application specification to a working MP-SoC prototype in FPGA technology with the (parallelized) application mapped onto it in only a matter of hours. During this traversal, which offers a high degree of automation, guidance is provided by Daedalus integrated system-level design space exploration environment. We show that Daedalus offers remarkable potentials for quickly experimenting with different MP-SoC architectures and exploring system-level design options during the very early stages of design. Using a case study with a Motion-JPEG encoder application, we illustrate Daedalus design steps and demonstrate its efficiency.

System level design with spade: an M-JPEG case study

Presents and evaluates the SPADE (System level Performance Analysis and Design space Exploration) methodology through an illustrative case study. SPADE is a method and tool for architecture exploration of heterogeneous signal processing systems. In this case study we start from an M-JPEG application and use SPADE to evaluate alternative multiprocessor architectures for implementing this application. SPADE follows the Y-chart paradigm for system level design; application and architecture are modeled separately and mapped onto each other in an explicit design step. SPADE permits architectures to be modeled at an abstract level using a library of generic building blocks, thereby reducing the cost of model construction and simulation. The case study shows that SPADE supports efficient exploration of candidate architectures; models can be easily constructed, modified and simulated in order to quickly evaluate alternative system implementations.

Handbook of Signal Processing Systems

Handbook of Signal Processing Systemsis organized in three parts. The first part motivates representative applications that drive and apply state-of-the art methods for design and implementation of signal processing systems; the second part discusses architectures for implementing these applications; the third part focuses on compilers and simulation tools, describes models of computation and their associated design tools and methodologies. This handbook is an essential tool for professionals in many fields and researchers of all levels.

Multi-processor system design with ESPAM

For modern embedded systems, the complexity of embedded applications has reached a point where the performance requirements of these applications can no longer be supported by embedded system architectures based on a single processor. Thus, the emerging embedded System-on-Chip platforms are increasingly becoming multiprocessor architectures. As a consequence, two major problems emerge, i.e., how to design and how to program such multiprocessor platforms in a systematic and automated way in order to reduce the design time and to satisfy the performance needs of applications executed on these platforms. Unfortunately, most of the current design methodologies and tools are based on Register Transfer Level (RTL) descriptions, mostly created by hand. Such methodologies are inadequate, because creating RTL descriptions of complex multiprocessor systems is error-prone and time consuming. As an efficient solution to these two problems, in this paper we propose a methodology and techniques implemented in a tool called ESPAM for automated multiprocessor system design and implementation. ESPAM moves the design specification from RTL to a higher, so called system level of abstraction. We explain how starting from system level platform, application, and mapping specifications, a multiprocessor platform is synthesized and programmed in a systematic and automated way. Furthermore, we present some results obtained by applying our methodology and ESPAM tool to automatically generate multiprocessor systems that execute a real-life application, namely a Motion-JPEG encoder.

A Methodology to Design Programmable Embedded Systems

Embedded systems architectures are increasingly becoming programmable, which means that an architecture can execute a set of applications instead of only one. This makes these systems cost-effective, as the same resources can be reused for another application by reprogramming the system. To design these programmable architectures, we present in this article a number of concepts of which one is the Y-chart approach. These concepts allow designers to perform a systematic exploration of the design space of architectures. Since this design space may be huge, it is narrowed down in a number of steps. The concepts presented in this article provide a methodology in which architectures can be obtained that satisfies a set of constraints while establishing enough flexibility to support a given set of applications.

Algorithmic transformation techniques for efficient exploration of alternative application instances

Following the Y-chart paradigm for designing a system, an application and an architecture are modeled separately and mapped onto each other in an explicit design step. Next, a performance analysis for alternative application instances, architecture instances and mappings has to be done, thereby exploring the design space of the target system. Deriving alternative application instances is not trivially done. Nevertheless, many instances of a single application exist that are worth being derived for exploration. We present algorithmic transformation techniques for systematic and fast generation of alternative application instances that express task-level concurrency hidden in an application in some degree of explicitness. These techniques help a system designer to speedup significantly the design space exploration process.

Translating affine nested-loop programs to process networks

New heterogeneous multiprocessor platforms are emerging that are typically composed of loosely coupled components that exchange data using programmable interconnections. The components can be CPUs or DSPs, specialized IP cores, reconfigurable units, or memories. To program such platform, we use the Process Network (PN) model of computation. The localized control and distributed memory are the two key ingredients of a PN allowing us to program the platforms. The localized control matches the loosely coupled components and the distributed memory matches the style of interaction between the components. To obtain applications in a PN format, we have built the Compaan compiler that translates affine nested-loop programs into functionally equivalent PNs. In this paper, we describe a novel analytical translation procedure we use in our compiler that is based on integer linear programming. The translation procedure consists of four main steps and we will present each step by describing the main idea involved, followed by a representative example.