33 research outputs found
Object-oriented domain specific compilers for programming FPGAs
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Fault and Defect Tolerant Computer Architectures: Reliable Computing With Unreliable Devices
This research addresses design of a reliable computer from unreliable device technologies. A system architecture is developed for a fault and defect tolerant (FDT) computer. Trade-offs between different techniques are studied and yield and hardware cost models are developed. Fault and defect tolerant designs are created for the processor and the cache memory. Simulation results for the content-addressable memory (CAM)-based cache show 90% yield with device failure probabilities of 3 x 10(-6), three orders of magnitude better than non fault tolerant caches of the same size. The entire processor achieves 70% yield with device failure probabilities exceeding 10(-6). The required hardware redundancy is approximately 15 times that of a non-fault tolerant design. While larger than current FT designs, this architecture allows the use of devices much more likely to fail than silicon CMOS. As part of model development, an improved model is derived for NAND Multiplexing. The model is the first accurate model for small and medium amounts of redundancy. Previous models are extended to account for dependence between the inputs and produce more accurate results
FPGA Processor In Memory Architectures (PIMs): Overlay or Overhaul ?
The dominance of machine learning and the ending of Moore's law have renewed
interests in Processor in Memory (PIM) architectures. This interest has
produced several recent proposals to modify an FPGA's BRAM architecture to form
a next-generation PIM reconfigurable fabric. PIM architectures can also be
realized within today's FPGAs as overlays without the need to modify the
underlying FPGA architecture. To date, there has been no study to understand
the comparative advantages of the two approaches. In this paper, we present a
study that explores the comparative advantages between two proposed custom
architectures and a PIM overlay running on a commodity FPGA. We created PiCaSO,
a Processor in/near Memory Scalable and Fast Overlay architecture as a
representative PIM overlay. The results of this study show that the PiCaSO
overlay achieves up to 80% of the peak throughput of the custom designs with
2.56x shorter latency and 25% - 43% better BRAM memory utilization efficiency.
We then show how several key features of the PiCaSO overlay can be integrated
into the custom PIM designs to further improve their throughput by 18%, latency
by 19.5%, and memory efficiency by 6.2%.Comment: Accepted in 2023 33rd International Conference on Field-Programmable
Logic and Applications (FPL
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A Novel Reconfiguration Scheme in Quantum-Dot Cellular Automata for Energy Efficient Nanocomputing
Quantum-Dot Cellular Automata (QCA) is currently being investigated as an alternative to CMOS technology. There has been extensive study on a wide range of circuits from simple logical circuits such as adders to complex circuits such as 4-bit processors. At the same time, little if any work has been done in considering the possibility of reconfiguration to reduce power in QCA devices. This work presents one of the first such efforts when considering reconfigurable QCA architectures which are expected to be both robust and power efficient. We present a new reconfiguration scheme which is highly robust and is expected to dissipate less power with respect to conventional designs. An adder design based on the reconfiguration scheme will be presented in this thesis, with a detailed power analysis and comparison with existing designs. In order to overcome the problems of routing which comes with reconfigurability, a new wire crossing mechanism is also presented as part of this thesis
A survey of fault-tolerance algorithms for reconfigurable nano-crossbar arrays
ACM Comput. Surv. Volume 50, issue 6 (November 2017)Nano-crossbar arrays have emerged as a promising and viable technology to improve computing performance of electronic circuits beyond the limits of current CMOS. Arrays offer both structural efficiency with reconfiguration and prospective capability of integration with different technologies. However, certain problems need to be addressed, and the most important one is the prevailing occurrence of faults. Considering fault rate projections as high as 20% that is much higher than those of CMOS, it is fair to expect sophisticated fault-tolerance methods. The focus of this survey article is the assessment and evaluation of these methods and related algorithms applied in logic mapping and configuration processes. As a start, we concisely explain reconfigurable nano-crossbar arrays with their fault characteristics and models. Following that, we demonstrate configuration techniques of the arrays in the presence of permanent faults and elaborate on two main fault-tolerance methodologies, namely defect-unaware and defect-aware approaches, with a short review on advantages and disadvantages. For both methodologies, we present detailed experimental results of related algorithms regarding their strengths and weaknesses with a comprehensive yield, success rate and runtime analysis. Next, we overview fault-tolerance approaches for transient faults. As a conclusion, we overview the proposed algorithms with future directions and upcoming challenges.This work is supported by the EU-H2020-RISE project NANOxCOMP no 691178 and the TUBITAK-Career
project no 113E760
Interconnect yield analysis and fault tolerance for field programmable gate arrays
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Using embedded hardware monitor cores in critical computer systems
The integration of FPGA devices in many different architectures and services
makes monitoring and real time detection of errors an important concern in FPGA
system design. A monitor is a tool, or a set of tools, that facilitate analytic
measurements in observing a given system. The goal of these observations is
usually the performance analysis and optimisation, or the surveillance of the system.
However, System-on-Chip (SoC) based designs leave few points to attach external
tools such as logic analysers. Thus, an embedded error detection core that allows
observation of critical system nodes (such as processor cores and buses) should
enforce the operation of the FPGA-based system, in order to prevent system
failures. The core should not interfere with system performance and must ensure
timely detection of errors.
This thesis is an investigation onto how a robust hardware-monitoring module
can be efficiently integrated in a target PCI board (with FPGA-based application processing
features) which is part of a critical computing system. [Continues.