Reliable, energy-efficient, and secure silicon photonic network-on-chip design for manycore architectures
Date
2018
Authors
Chittamuru, Sai Vineel Reddy, author
Pasricha, Sudeep, advisor
Jayasumana, Anura, committee member
Roy, Sourajeet, committee member
Malaiya, Yashwant K., committee member
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Abstract
Advances in technology scaling over the past s+H91everal decades have enabled the integration of billions of transistors on a single die. Such a massive number of transistors has allowed multiple processing cores and significant memory to be integrated on a chip, to meet the rapidly growing performance demands of modern applications. These on-chip processing and memory components require an efficient mechanism to communicate with each other. Thus emerging manycore architectures with high core counts have adopted scalable packet switched electrical network-on-chip (ENoC) fabrics to support on-chip transfers. But with several hundreds to thousands of on-chip cores expected to become a reality in the near future, ENoCs are projected to suffer from cripplingly high power dissipation and limited performance. Recent developments in the area of silicon photonics have enabled the integration of on-chip photonic interconnects with CMOS circuits, enabling photonic networks-on-chip (PNoCs) that can offer ultra-high bandwidth, reduced power dissipation, and lower latency than ENoCs. There are several challenges that hinder the commercial adoption of these PNoC architectures. Especially, the operation of silicon photonic components is very sensitive to thermal variations (TV) and process variations (PV) that frequently occur on a chip. These variations and their mitigation techniques create significant reliability issues and increase energy costs in PNoCs. Furthermore, photonic components are susceptible to intrinsic crosstalk noise and aging, which demands higher energy for reliable communication. Moreover, contention in photonic waveguides as well as laser power distribution overheads also reduce performance and energy-efficiency. In addition, hardware trojans (HTs) in the electrical circuitry of photonic components lead to covert data snooping from shared photonic waveguides and introduces serious hardware security threats. To address these challenges, in this dissertation we propose a cross-layer framework towards the design of reliable, secure, and energy-efficient PNoC architectures. We devise layer-specific solutions for PNoC design as part of our framework: (i) we propose device-level enhancements to adapt to TV, and to mitigate heterodyne crosstalk and intermodulation effect induced heterodyne crosstalk; we also analyze aging in photonic components and explore its impact on PNoCs; (ii) at the circuit-level we propose PV-aware homodyne and heterodyne crosstalk mitigation mechanisms, a PV-aware security enhancement mechanism, and TV- and PV-aware photonic component assignment mechanisms; (iii) at the architecture-level we propose new application specific and reconfigurable PNoC architectures to improve photonic channel utilization, a laser power management scheme across components of PNoC architectures, and a reservation-assisted security enhancement scheme to improve security in PNoC architectures; and (iv) at the system-level we propose TV and PV aware thread migration schemes and application scheduling schemes that exploit adaptive application degree of parallelism (DoP). In addition to layer-specific enhancements, we also combine techniques across layers to create cross-layer optimization strategies to aggressively improve reliability and energy-efficiency in PNoC architectures. In our SPECTRA and LIBRA frameworks we combine system-level and circuit-level enhancements for TV management in PNoCs. In our 'Island of Heater' framework we combine system-level and device-level enhancements for TV management in PNoCs. We combine device-level and circuit-level enhancements for heterodyne crosstalk mitigation in our PICO and HYDRA frameworks. Our proposed BiGNoC architecture uses architectural-level enhancements and system-level application scheduling to improve its performance and energy-efficiency. Lastly, in our SOTERIA framework we combine circuit-level and architecture-level enhancements to enable secure communication in DWDM-based PNoC architectures.
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Subject
hardware security
photonic network on chip
reliability
MR aging
crosstalk noise
process and thermal variations