A Survey of Techniques For Improving Energy Efficiency in Embedded Computing Systems

Recent technological advances have greatly improved the performance and features of embedded systems. With the number of just mobile devices now reaching nearly equal to the population of earth, embedded systems have truly become ubiquitous. These trends, however, have also made the task of managing their power consumption extremely challenging. In recent years, several techniques have been proposed to address this issue. In this paper, we survey the techniques for managing power consumption of embedded systems. We discuss the need of power management and provide a classification of the techniques on several important parameters to highlight their similarities and differences. This paper is intended to help the researchers and application-developers in gaining insights into the working of power management techniques and designing even more efficient high-performance embedded systems of tomorrow

SATAY: A Streaming Architecture Toolflow for Accelerating YOLO Models on FPGA Devices

AI has led to significant advancements in computer vision and image processing tasks, enabling a wide range of applications in real-life scenarios, from autonomous vehicles to medical imaging. Many of those applications require efficient object detection algorithms and complementary real-time, low latency hardware to perform inference of these algorithms. The YOLO family of models is considered the most efficient for object detection, having only a single model pass. Despite this, the complexity and size of YOLO models can be too computationally demanding for current edge-based platforms. To address this, we present SATAY: a Streaming Architecture Toolflow for Accelerating YOLO. This work tackles the challenges of deploying stateof-the-art object detection models onto FPGA devices for ultralow latency applications, enabling real-time, edge-based object detection. We employ a streaming architecture design for our YOLO accelerators, implementing the complete model on-chip in a deeply pipelined fashion. These accelerators are generated using an automated toolflow, and can target a range of suitable FPGA devices. We introduce novel hardware components to support the operations of YOLO models in a dataflow manner, and off-chip memory buffering to address the limited on-chip memory resources. Our toolflow is able to generate accelerator designs which demonstrate competitive performance and energy characteristics to GPU devices, and which outperform current state-of-the-art FPGA accelerators

High-Level Synthesis Hardware Design for FPGA-Based Accelerators: Models, Methodologies, and Frameworks

Hardware accelerators based on field programmable gate array (FPGA) and system on chip (SoC) devices have gained attention in recent years. One of the main reasons is that these devices contain reconfigurable logic, which makes them feasible for boosting the performance of applications. High-level synthesis (HLS) tools facilitate the creation of FPGA code from a high level of abstraction using different directives to obtain an optimized hardware design based on performance metrics. However, the complexity of the design space depends on different factors such as the number of directives used in the source code, the available resources in the device, and the clock frequency. Design space exploration (DSE) techniques comprise the evaluation of multiple implementations with different combinations of directives to obtain a design with a good compromise between different metrics. This paper presents a survey of models, methodologies, and frameworks proposed for metric estimation, FPGA-based DSE, and power consumption estimation on FPGA/SoC. The main features, limitations, and trade-offs of these approaches are described. We also present the integration of existing models and frameworks in diverse research areas and identify the different challenges to be addressed

Optimising algorithm and hardware for deep neural networks on FPGAs

This thesis proposes novel algorithm and hardware optimisation approaches to accelerate Deep Neural Networks (DNNs), including both Convolutional Neural Networks (CNNs) and Bayesian Neural Networks (BayesNNs). The first contribution of this thesis is to propose an adaptable and reconfigurable hardware design to accelerate CNNs. By analysing the computational patterns of different CNNs, a unified hardware architecture is proposed for both 2-Dimension and 3-Dimension CNNs. The accelerator is also designed with runtime adaptability, which adopts different parallelism strategies for different convolutional layers at runtime. The second contribution of this thesis is to propose a novel neural network architecture and hardware design co-optimisation approach, which improves the performance of CNNs at both algorithm and hardware levels. Our proposed three-phase co-design framework decouples network training from design space exploration, which significantly reduces the time-cost of the co-optimisation process. The third contribution of this thesis is to propose an algorithmic and hardware co-optimisation framework for accelerating BayesNNs. At the algorithmic level, three categories of structured sparsity are explored to reduce the computational complexity of BayesNNs. At the hardware level, we propose a novel hardware architecture with the aim of exploiting the structured sparsity for BayesNNs. Both algorithmic and hardware optimisations are jointly applied to push the performance limit.Open Acces

Coarse-grained reconfigurable array architectures

Coarse-Grained Reconfigurable Array (CGRA) architectures accelerate the same inner loops that benefit from the high ILP support in VLIW architectures. By executing non-loop code on other cores, however, CGRAs can focus on such loops to execute them more efficiently. This chapter discusses the basic principles of CGRAs, and the wide range of design options available to a CGRA designer, covering a large number of existing CGRA designs. The impact of different options on flexibility, performance, and power-efficiency is discussed, as well as the need for compiler support. The ADRES CGRA design template is studied in more detail as a use case to illustrate the need for design space exploration, for compiler support and for the manual fine-tuning of source code

Performance Optimization of Memory Intensive Applications on FPGA Accelerator

L'abstract è presente nell'allegato / the abstract is in the attachmen