Low-cost sensing with ring oscillator arrays for healthier reconfigurable systems

Abstract

Electronic systems on a chip increasingly suffer from component variation, voltage noise, thermal hotspots, and other subtle physical phenomena. Systems with reconfigurability have unique opportunities for adapting to such effects. Required, however, are low-cost, fine-grained methods for sensing physical parameters. This article presents powerful, novel approaches to online sensing, including methods for designing compact reconfigurable sensors, low-cost threshold detection, and several enhanced measurement procedures. Together, the approaches help enable systems to autonomously uncover a wealth of physical information. A highly efficient counter and improved ring oscillator are introduced, enabling an entire sensor node in just 8 Virtex-5 LUTs. We describe how variations can be measured in delay, temperature, switching-induced IR drop, and leakage-induced IR drop. We demonstrate the proposed approach with an experimental system based on a Virtex-5, instrumented with over 100 sensors at an overhead of only 1.3%. Results from thermally controlled experiments provide some surprising insights and illustrate the utility of the approach. Online sensing can help open the door to physically adaptive computing, including fine-grained power, reliability, and health management schemes for systems on a chip. ACM Reference Format:Zick, K. M. and Hayes, J. P. 2012. Low-cost sensing with ring oscillator arrays for healthier reconfigurable systems.

Exploration of ring oscillator design space for temperature measurements on FPGAs

“…It shows that, while noise decreases with the number of inverters, eventually approaching the level of quantization noise, the resolution also decreases, giving rise to a broad optimum in sensor performance at 47 inverters. Use of latches: As suggested in [4], slice latches that are held in the open state can be built into the oscillator circuit. An advantage of this is, that the latches are basically free resources, since on the FPGA each LUT has an associated latch/flip-flop component that can be connected to the LUT's output without the use of additional routing resources.…”

“…Recently, Zick and Hayes [4] proposed a low cost RObased sensor to measure not only temperature but also delay, leakage and dynamic power on a Xilinx Virtex-5 FPGA.…”

“…1. Simplified schematic of our temperature sensor sors using a daisy chain as proposed in [4]. In contrast to related work, we did an exhaustive study to evaluate the influence of different parameters-such as the measurement period, number of inverters and use of latches-on the measurement performance of RO-based temperature sensors.…”

“…Thus, many researchers employ ring oscillators (ROs) as temperature sensors on FPGAs [2,3,4]. Research on RObased temperature sensors includes sensor placement [5], sensor calibration [6,7] and workload effects on the measurement performance [8].…”

Moving and Relocating: A Logical Framework of Service Migration for Software System Survivability

“…For instance, if the number of fault types becomes large or different actions/events must be taken following error detection, fault tolerance and damage masking may become difficult. Reconfiguration ( [4][5][6], to cite a few) may provide a solution to avoid intensive replication; but it requires a change of the functional specifications of the platforms currently in operation, which may have already been compromised during an attack. Different from those techniques, strategic migration allows the critical services to be continuously provided on other trustworthy platforms without incurring expensive resource duplication or attempting to reconfigure a system which cannot be trusted.…”