The scaling of microchip technologies has enabled large scale systems-on-chip (SoC). Network-on-chip (NoC) research addresses global communication in SoC, involving (i) a move from computation-centric to communication-centric design and (ii) the implementation of scalable communication structures. This survey presents a perspective on existing NoC research. We define the following abstractions: system, network adapter, network, and link to explain and structure the fundamental concepts. First, research relating to the actual network design is reviewed. Then system level design and modeling are discussed. We also evaluate performance analysis techniques. The research shows that NoC constitutes a unification of current trends of intrachip communication rather than an explicit new alternative.

/pdf/a-survey-of-research-and-practices-of-network-on-chip-2rc0mlsrfq.pdf

A survey of research and practices of Network-on-chip

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain-inspired computing. Performance metrics desirable for large-scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented.

https://iopscience.iop.org/article/10.1088/0957-4484/24/38/382001/pdf

Synaptic electronics: materials, devices and applications

Multiprocessor system-on-chip (MP-SoC) platforms are emerging as an important trend for SoC design. Power and wire design constraints are forcing the adoption of new design methodologies for system-on-chip (SoC), namely, those that incorporate modularity and explicit parallelism. To enable these MP-SoC platforms, researchers have recently pursued scaleable communication-centric interconnect fabrics, such as networks-on-chip (NoC), which possess many features that are particularly attractive for these. These communication-centric interconnect fabrics are characterized by different trade-offs with regard to latency, throughput, energy dissipation, and silicon area requirements. In this paper, we develop a consistent and meaningful evaluation methodology to compare the performance and characteristics of a variety of NoC architectures. We also explore design trade-offs that characterize the NoC approach and obtain comparative results for a number of common NoC topologies. To the best of our knowledge, this is the first effort in characterizing different NoC architectures with respect to their performance and design trade-offs. To further illustrate our evaluation methodology, we map a typical multiprocessing platform to different NoC interconnect architectures and show how the system performance is affected by these design trade-offs.

/pdf/performance-evaluation-and-design-trade-offs-for-network-on-2r2qk1xk70.pdf

Performance evaluation and design trade-offs for network-on-chip interconnect architectures

Approximate computing has recently emerged as a promising approach to energy-efficient design of digital systems. Approximate computing relies on the ability of many systems and applications to tolerate some loss of quality or optimality in the computed result. By relaxing the need for fully precise or completely deterministic operations, approximate computing techniques allow substantially improved energy efficiency. This paper reviews recent progress in the area, including design of approximate arithmetic blocks, pertinent error and quality measures, and algorithm-level techniques for approximate computing.

/pdf/approximate-computing-an-emerging-paradigm-for-energy-z7hetfdl3q.pdf

Approximate computing: An emerging paradigm for energy-efficient design

The objective of this paper is to introduce self-similarity as a fundamental property exhibited by the bursty traffic between on-chip modules in typical MPEG-2 video applications. Statistical tests performed on relevant traces extracted from common video clips establish unequivocally the existence of self-similarity in video traffic. Using a generic tile-based communication architecture, we discuss the implications of our findings on on-chip buffer space allocation and present quantitative evaluations for typical video streams. We also describe a technique for synthetically generating traces having statistical properties similar to those obtained from real video clips. Our proposed technique speeds up buffer simulations, allows media system designers to explore architectures rapidly and use large media data benchmarks more efficiently. We believe that our findings open new directions of research with deep implications on some fundamental issues in on-chip networks design for multimedia applications.

http://www.scarpaz.com/2100-papers/traffic_TVLSI04.pdf

On-chip traffic modeling and synthesis for MPEG-2 video applications

The objective of this paper is to introduce self-similarity as a fundamental property exhibited by the bursty traffic between on-chip modules in typical MPEG-2 video applications. Statistical tests performed on relevant traces extracted from common video clips establish unequivocally the existence of self-similarity in video traffic. Using a generic communication architecture, we also discuss the implications of our findings on on-chip buffer space allocation and present quantitative evaluations for typical video streams. We believe that our findings open up new directions of research with deep implications on some fundamental issues in on-chip network design for multimedia applications.

/pdf/traffic-analysis-for-on-chip-networks-design-of-multimedia-13pgczz1ym.pdf

Traffic analysis for on-chip networks design of multimedia applications

In this paper, we present an interprocessor communication-aware task scheduling algorithm applicable to a multiprocessor system executing an application with dependent tasks. Our algorithm takes the application task graph and the architecture graph as inputs, assigns the tasks to processors and then schedules them. As main theoretical contribution, the algorithm we propose reduces the overall systems energy by (i) reducing the total interprocessor communication and (ii) executing certain cycles at a lower voltage level. Experimental results show that by tuning the parameter for communication awareness, a schedule using our algorithm can reduce up to 80% interprocessor communication in a complex video/audio application (compared to a schedule which is only voltage-selection aware) without losing much in the number of cycles executed at lower voltage.

/pdf/communication-aware-task-scheduling-and-voltage-selection-3zf0n23yy8.pdf

Communication-Aware Task Scheduling and Voltage Selection for Total Systems Energy Minimization

Presented is an energy-efficient motion estimation architecture using error-tolerance. The technique employs overscaling of the supply voltage (voltage overscaling (VOS)) to reduce power at the expense of timing errors, which are then corrected using algorithmic noise-tolerance (ANT) techniques. Referred to as input subsampled replica ANT (ISR-ANT), the proposed technique incorporates an input subsampled replica of the main sum of absolute difference (MSAD) block for obtaining the motion vectors in the presence of errors induced by VOS. Simulations show that the proposed technique can save up to 60% power over an optimal error-free present day system in a 130nm CMOS technology. Power savings increase to 79% in a 45nm predictive process technology.

/pdf/energy-efficient-motion-estimation-using-error-tolerance-d5mpl86tu9.pdf

Energy-efficient motion estimation using error-tolerance

In this paper, we propose an energy-efficient motion estimation architecture. The proposed architecture employs the principle of error-resiliency to combat logic level timing errors that may arise in average-case designs in presence of process variations and/or due to overscaling of the supply voltage [voltage overscaling (VOS)] and thereby achieves power reduction. Error-resiliency is incorporated via algorithmic noise-tolerance (ANT). Referred to as input subsampled replica ANT (ISR-ANT), the proposed technique incorporates an input subsampled replica of the main sum-of-absolute-difference (MSAD) block for detecting and correcting errors in the MSAD block. Simulations show that the proposed technique can save up to 60% power over an optimal error-free system in a 130-nm CMOS technology. These power savings increase to 78% in a 45-nm predictive process technology. Performance of the ISR-ANT architecture in the presence of process variations indicates that average peak signal-to-noise ratio (PSNR) of the ISR-ANT architecture increases by up to 1.8 dB over that of the conventional architecture in 130-nm IBM process technology. Furthermore, the PSNR variation (sigma/mu) is also reduced by 7times over that of the conventional architecture at the slow corner while achieving a power reduction of 33%.

G.V. Varatkar

Papers

On-chip traffic modeling and synthesis for MPEG-2 video applications

Traffic analysis for on-chip networks design of multimedia applications

Communication-Aware Task Scheduling and Voltage Selection for Total Systems Energy Minimization

Energy-efficient motion estimation using error-tolerance

Error-Resilient Motion Estimation Architecture