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 －

Fault-Tolerant Computer System Design by Dhiraj K. Pradhan 550 pp. $72 Prentice Hall Upper Saddle River, N.J. 1996 ISBN 0-13-057887-8

Fault-tolerant computer system design

Estimation of soft error sensitivity is crucial in order to devise optimal mitigation solutions that can satisfy reliability requirements with reduced impact on area, performance, and power consumption. In particular, the estimation of Single Event Transient (SET) effects for complex systems that include a microprocessor is challenging, due to the huge potential number of different faults and effects that must be considered, and the delay-dependent nature of SET effects. In this paper, we propose a multilevel FPGA emulation-based fault injection approach for evaluation of SET effects called AMUSE (Autonomous MUltilevel emulation system for Soft Error evaluation). This approach integrates Gate level and Register-Transfer level models of the circuit under test in a FPGA and is able to switch to the appropriate model as needed during emulation. Fault injection is performed at the Gate level, which provides delay accuracy, while fault propagation across clock cycles is performed at the Register-Transfer level for higher performance. Experimental results demonstrate that AMUSE can emulate soft error effects for complex circuits including microprocessors and memories, considering the real delays of an ASIC technology, and support massive fault injection campaigns, in the order of tens of millions of faults within acceptable time.

Soft Error Sensitivity Evaluation of Microprocessors by Multilevel Emulation-Based Fault Injection

Hardening SoCs against transient faults requires new techniques able to combine high fault detection capabilities with the usual requirements of SoC design flow, e.g., reduced design-time, low area overhead, and reduced (or null) accessibility to source core descriptions. This paper proposes a new hybrid approach which combines hardening software transformations with the introduction of an Infrastructure IP with reduced memory and performance overheads. The proposed approach targets faults affecting the memory elements storing both the code and the data, independently of their location (inside or outside the processor). Extensive experimental results, including comparisons with previous approaches, are reported, which allow practically evaluating the characteristics of the method in terms of fault detection capabilities and area, memory, and performance overheads.

A new hybrid fault detection technique for systems-on-a-chip

The paper presents, and discusses the rationale behind, a method for structuring complex computing systems by the use of what we term “recovery blocks”, “conversations” and “fault-tolerant interfaces”. The aim is to facilitate the provision of dependable error detection and recovery facilities which can cope with errors caused by residual design inadequacies, particularly in the system software, rather than merely the occasional malfunctioning of hardware components.

System Structure for Software Fault Tolerance

Clock-gating and power-gating have proven to be very effective solutions for reducing dynamic and static power, respectively. The two techniques may be coupled in such a way that the clock-gating information can be used to drive the control signal of the power-gating circuitry, thus providing additional leakage minimization conditions w.r.t. those manually inserted by the designer. This conceptual integration, however, poses several challenges when moved to industrial design flows. Although both clock and power-gating are supported by most commercial synthesis tools, their combined implementation requires some flexibility in the back-end tools that is not currently available. This paper presents a layout-oriented synthesis flow which integrates the two techniques and that relies on leading-edge, commercial EDA tools. Starting from a gated-clock netlist, we partition the circuit in a number of clusters that are implicitly determined by the groups of cells that are clock-gated by the same register. Using a row-based granularity, we achieve runtime leakage reduction by inserting dedicated sleep transistors for each cluster. The entire flow has been benchmarked on a industrial design mapped onto a commercial, 65nm CMOS technology library.

Enabling concurrent clock and power gating in an industrial design flow

Clock gating and power gating are two of the most effective techniques that are applied today for reducing dynamic and leakage power, respectively, in digital CMOS circuits. The combined use of the two solutions, however, poses some challenges in terms of practical integration of the required control logic and the power/timing overhead associated to it. This paper presents an analysis methodology and a prototype CAD tool that support the designer in understanding when the joint application of clock gating and power gating may result in significant power savings.

Integrating Clock Gating and Power Gating for Combined Dynamic and Leakage Power Optimization in Digital CMOS Circuits

High integration levels, coupled with the increased sensitivity to soft errors even at ground level, make the task of guaranteeing adequate dependability levels more difficult then ever. In this paper, we propose to adopt low-cost infrastructure-intellectual-property (I-IP) cores in conjunction with software-based techniques to perform soft error detection. Experimental results are reported that show the effectiveness of the proposed approach.

Hybrid soft error detection by means of infrastructure IP cores [SoC implementation]

In sub-micron technology circuits high integration levels coupled with the increased sensitivity to soft errors even at ground level make the task of guaranteeing systems' dependability more difficult than ever. In this paper we present a new approach to detect control-flow errors by exploiting a low-cost infrastructure intellectual property (I-IP) core that works in cooperation with software-based techniques. The proposed approach is particularly suited when the system to be hardened is implemented as a system-on-chip (SoC), since the I-IP can be added easily and it is independent on the application. Experimental results are reported showing the effectiveness of the proposed approach.

L. Bolzani

Papers

A new hybrid fault detection technique for systems-on-a-chip

Enabling concurrent clock and power gating in an industrial design flow

Integrating Clock Gating and Power Gating for Combined Dynamic and Leakage Power Optimization in Digital CMOS Circuits

Hybrid soft error detection by means of infrastructure IP cores [SoC implementation]

On-line detection of control-flow errors in SoCs by means of an infrastructure IP core