Resource-efficient dynamic partial reconfiguration on FPGAs for space instruments

Field-Programmable Gate Arrays (FPGAs) provide highly flexible platforms to implement sophisticated data processing for scientific space instruments. The dynamic partial reconfiguration (DPR) capability of FPGAs allows it to schedule HW tasks. While this feature adds another dimension of processing power that can be exploited without significantly increasing system complexity and power consumption, there are still several challenges for an efficient DPR use. State-of-the-art concepts concentrate either on resource-efficient implementations at design time or flexible HW task scheduling at runtime. In this paper we propose a balanced algorithm that considers both optimization goals and is well suited for resource-limited space applications

Hardware and Software Task Scheduling for ARM-FPGA Platforms

ARM-FPGA coupled platforms allow accelerating the computation of specific algorithms by executing them in the FPGA fabric. Several computation steps of our case study for a stereo vision application have been accelerated by hardware implementations. Dynamic Partial Reconfiguration places these hardware tasks in the programmable logic at appropriate times. For an efficient scheduling, it needs to be decided when and where to execute a task. Although there already exist hardware/software scheduling strategies and algorithms, none exploit all possible optimization techniques: re-use, prefetching, parallelization, and pipelining of hardware tasks. The scheduling algorithm proposed in this paper takes this into account and optimizes for the objectives latency/throughput and power/energy

FPGA dynamic and partial reconfiguration : a survey of architectures, methods, and applications

Dynamic and partial reconfiguration are key differentiating capabilities of field programmable gate arrays (FPGAs). While they have been studied extensively in academic literature, they find limited use in deployed systems. We review FPGA reconfiguration, looking at architectures built for the purpose, and the properties of modern commercial architectures. We then investigate design flows, and identify the key challenges in making reconfigurable FPGA systems easier to design. Finally, we look at applications where reconfiguration has found use, as well as proposing new areas where this capability places FPGAs in a unique position for adoption

Hardware task scheduling for partially reconfigurable FPGAs

Summarization: Partial reconfiguration (PR) of FPGAs can be used to dynamically extend and adapt the functionality of computing systems, swapping in and out HW tasks. To coordinate the on-demand task execution, we propose and implement a run time system manager for scheduling software (SW) tasks on available processor(s) and hardware (HW) tasks on any number of reconfigurable regions of a partially reconfigurable FPGA. Fed with the initial partitioning of the application into tasks, the corresponding task graph, and the available task mappings, the RTSM considers the runtime status of each task and region, e.g. busy, idle, scheduled for reconfiguration/execution etc., to execute tasks. Our RTSM supports task reuse and configuration prefetching to minimize reconfigurations, task movement among regions to efficiently manage the FPGA area, and RR reservation for future reconfiguration and execution. We validate its correctness using our RTSM to execute an image processing application on a ZedBoard platform. We also evaluate its features within a simulation framework, and find that despite the technology limitations, our approach can give promising results in terms of quality of scheduling.Presented on

TUKUTURI: eine dynamisch selbstrekonfigurierbare Softcore Prozessorarchitektur

Der Entwurf von Systemen zur digitalen Signalverarbeitung stellt den Entwickler vor stetig wachsende Herausforderungen, die durch zunehmende Komplexität von Anwendungen und die dafür benötigte Steigerung der Leistungsfähigkeit eingebetteter Systeme verursacht werden. Ein weiterer Aspekt neben der Leistungsfähigkeit ist die Flexibilität, die es erlaubt, Anwendungen und Algorithmen auch nach Auslieferung eines Systems zu verändern. Diese kann zum einen durch Verwendung von FPGAs erreicht werden, die eine Rekonfiguration der Hardware ermöglichen. Zum anderen können prozessorbasierte Systeme verwendet werden, die Flexibilität durch Programmierbarkeit bereitstellen. Anwendungsspezifische Anpassungen der Prozessorarchitektur und ein hohes Maß an paralleler Datenverarbeitung, beispielsweise durch VLIW-Prozessoren, stellen dabei Mittel zum Erreichen hoher Leistungen dar. Das Thema dieser Arbeit ist die Untersuchung eines Entwurfsprozesses für anwendungsspezifische Prozessorsysteme. Dieser basiert auf einem flexiblen SIMD-VLIW-Prozessor, der in großem Umfang konfiguriert und durch zusätzliche Hardwaremodule erweitert werden kann. Zur Exploration des Entwurfsraums werden Werkzeuge zur Analyse von Prozessorkonfigurationen in realen Anwendungen bereitgestellt sowie Methoden zur automatisierten Adaption der Architektur auf Basis dieser Analyseergebnisse untersucht. Die Kompilierung von Anwendungen für VLIW-Architekturen wird aufgrund der kombinatorischen Komplexität üblicherweise mittels statischer Heuristiken durchgeführt, wodurch eine optimale Adaption an flexible Architekturen erschwert werden kann. Daher werden hier dynamische Methoden zur Codegenerierung, die auf evolutionären Algorithmen basieren, untersucht. Die Umsetzung der Architektur als Softcore auf einem FPGA bietet zusätzlich die Möglichkeit der dynamischen Adaption der Hardware zur Laufzeit. Diese Möglichkeiten und deren Einfluss auf die Leistungsfähigkeit der Prozessorsysteme werden ebenfalls untersucht. Die Analyse des Entwurfsprozesses in einer exemplarischen Anwendung der bildbasierten Objekterkennung und der Vergleich mit Implementierungen auf einem MIPS-Softcore bzw. VLIW-DSP zeigen die Eignung der Methoden zur Adaption von Softcore-Prozessoren und der EA-basierten Kompilierung von Anwendungen. Die dynamische Hardwarerekonfiguration zur Laufzeit kann bei reduziertem Flächenbedarf für die Hardware ohne Leistungsverlust eingesetzt werden

Efficient runtime placement management for high performance and reliability in COTS FPGAs

Designing high-performance, fault-tolerant multisensory electronic systems for hostile environments such as nuclear plants and outer space within the constraints of cost, power and flexibility is challenging. Issues such as ionizing radiation, extreme temperature and ageing can lead to faults in the electronics of these systems. In addition, the remote nature of these environments demands a level of flexibility and autonomy in their operations. The standard practice of using specially hardened electronic devices for such systems is not only very expensive but also has limited flexibility. This thesis proposes novel techniques that promote the use of Commercial Off-The- Shelf (COTS) reconfigurable devices to meet the challenges of high-performance systems for hostile environments. Reconfigurable hardware such as Field Programmable Gate Arrays (FPGA) have a unique combination of flexibility and high performance. The flexibility offered through features such as dynamic partial reconfiguration (DPR) can be harnessed not only to achieve cost-effective designs as a smaller area can be used to execute multiple tasks, but also to improve the reliability of a system as a circuit on one portion of the device can be physically relocated to another portion in the case of fault occurrence. However, to harness these potentials for high performance and reliability in a cost-effective manner, novel runtime management tools are required. Most runtime support tools for reconfigurable devices are based on ideal models which do not adequately consider the limitations of realistic FPGAs, in particular modern FPGAs which are increasingly heterogeneous. Specifically, these tools lack efficient mechanisms for ensuring a high utilization of FPGA resources, including the FPGA area and the configuration port and clocking resources, in a reliable manner. To ensure high utilization of reconfigurable device area, placement management is a key aspect of these tools. This thesis presents novel techniques for the management of hardware task placement on COTS reconfigurable devices for high performance and reliability. To this end, it addresses design-time issues that affect efficient hardware task placement, with a focus on reliability. It also presents techniques to maximize the utilization of the FPGA area in runtime, including techniques to minimize fragmentation. Fragmentation leads to the creation of unusable areas due to dynamic placement of tasks and the heterogeneity of the resources on the chip. Moreover, this thesis also presents an efficient task reuse mechanism to improve the availability of the internal configuration infrastructure of the FPGA for critical responsibilities like error mitigation. The task reuse scheme, unlike previous approaches, also improves the utilization of the chip area by offering defragmentation. Task relocation, which involves changing the physical location of circuits is a technique for error mitigation and high performance. Hence, this thesis also provides a functionality-based relocation mechanism for improving the number of locations to which tasks can be relocated on heterogeneous FPGAs. As tasks are relocated, clock networks need to be routed to them. As such, a reliability-aware technique of clock network routing to tasks after placement is also proposed. Finally, this thesis offers a prototype implementation and characterization of a placement management system (PMS) which is an integration of the aforementioned techniques. The performance of most of the proposed techniques are tested using data processing tasks of a NASA JPL spectrometer application. The results show that the proposed techniques have potentials to improve the reliability and performance of applications in hostile environment compared to state-of-the-art techniques. The task optimization technique presented leads to better capacity to circumvent permanent faults on COTS FPGAs compared to state-of-the-art approaches (48.6% more errors were circumvented for the JPL spectrometer application). The proposed task reuse scheme leads to approximately 29% saving in the amount of configuration time. This frees up the internal configuration interface for more error mitigation operations. In addition, the proposed PMS has a worst-case latency of less than 50% of that of state-of- the-art runtime placement systems, while maintaining the same level of placement quality and resource overhead

Dynamic reconfiguration frameworks for high-performance reliable real-time reconfigurable computing

The sheer hardware-based computational performance and programming flexibility offered by reconfigurable hardware like Field-Programmable Gate Arrays (FPGAs) make them attractive for computing in applications that require high performance, availability, reliability, real-time processing, and high efficiency. Fueled by fabrication process scaling, modern reconfigurable devices come with ever greater quantities of on-chip resources, allowing a more complex variety of applications to be developed. Thus, the trend is that technology giants like Microsoft, Amazon, and Baidu now embrace reconfigurable computing devices likes FPGAs to meet their critical computing needs. In addition, the capability to autonomously reprogramme these devices in the field is being exploited for reliability in application domains like aerospace, defence, military, and nuclear power stations. In such applications, real-time computing is important and is often a necessity for reliability. As such, applications and algorithms resident on these devices must be implemented with sufficient considerations for real-time processing and reliability. Often, to manage a reconfigurable hardware device as a computing platform for a multiplicity of homogenous and heterogeneous tasks, reconfigurable operating systems (ROSes) have been proposed to give a software look to hardware-based computation. The key requirements of a ROS include partitioning, task scheduling and allocation, task configuration or loading, and inter-task communication and synchronization. Existing ROSes have met these requirements to varied extents. However, they are limited in reliability, especially regarding the flexibility of placing the hardware circuits of tasks on device’s chip area, the problem arising more from the partitioning approaches used. Indeed, this problem is deeply rooted in the static nature of the on-chip inter-communication among tasks, hampering the flexibility of runtime task relocation for reliability. This thesis proposes the enabling frameworks for reliable, available, real-time, efficient, secure, and high-performance reconfigurable computing by providing techniques and mechanisms for reliable runtime reconfiguration, and dynamic inter-circuit communication and synchronization for circuits on reconfigurable hardware. This work provides task configuration infrastructures for reliable reconfigurable computing. Key features, especially reliability-enabling functionalities, which have been given little or no attention in state-of-the-art are implemented. These features include internal register read and write for device diagnosis; configuration operation abort mechanism, and tightly integrated selective-area scanning, which aims to optimize access to the device’s reconfiguration port for both task loading and error mitigation. In addition, this thesis proposes a novel reliability-aware inter-task communication framework that exploits the availability of dedicated clocking infrastructures in a typical FPGA to provide inter-task communication and synchronization. The clock buffers and networks of an FPGA use dedicated routing resources, which are distinct from the general routing resources. As such, deploying these dedicated resources for communication sidesteps the restriction of static routes and allows a better relocation of circuits for reliability purposes. For evaluation, a case study that uses a NASA/JPL spectrometer data processing application is employed to demonstrate the improved reliability brought about by the implemented configuration controller and the reliability-aware dynamic communication infrastructure. It is observed that up to 74% time saving can be achieved for selective-area error mitigation when compared to state-of-the-art vendor implementations. Moreover, an improvement in overall system reliability is observed when the proposed dynamic communication scheme is deployed in the data processing application. Finally, one area of reconfigurable computing that has received insufficient attention is security. Meanwhile, considering the nature of applications which now turn to reconfigurable computing for accelerating compute-intensive processes, a high premium is now placed on security, not only of the device but also of the applications, from loading to runtime execution. To address security concerns, a novel secure and efficient task configuration technique for task relocation is also investigated, providing configuration time savings of up to 32% or 83%, depending on the device; and resource usage savings in excess of 90% compared to state-of-the-art