SPECTRA: A Framework for Thermal Reliability Management in Silicon-Photonic Networks-on-Chip

Abstract

Silicon nanophotonics technology is being considered for future networks-on-chip (NoCs) as it can enable high bandwidth density and lower latency with traversal of data at the speed of light. But the operation of photonic NoCs (PNoCs) is very sensitive to temperature variations that frequently occur on a chip. These variations can create significant reliability issues for PNoCs. For example, a microring resonator (MR) may resonate at another wavelength instead of its designated wavelength due to thermal variations, which can lead to bandwidth wastage and data corruption in PNoCs. This paper proposes a novel run-time framework called SPECTRA to overcome temperature-induced reliability issues in PNoCs. The framework consists of (i) a device-level reactive MR assignment mechanism that dynamically assigns a group of MRs to reliably modulate/receive data in a waveguide based on the chip thermal profile, and (ii) a system-level proactive thread migration technique to avoid on-chip thermal threshold violations and reduce MR tuning/trimming power by dynamically migrating threads between cores. Experimental results indicate that SPECTRA can satisfy on-chip thermal thresholds and maintain high NoC bandwidth while reducing total power by up to 61%, and thermal tuning/trimming power by up to 71% over state-of-the-art thermal management solutions.