
Proceedings Paper
Towards energy-efficient photonic interconnectsFormat | Member Price | Non-Member Price |
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Paper Abstract
Silicon photonics have emerged as a promising solution to meet the growing demand for high-bandwidth, low-latency, and
energy-efficient on-chip and off-chip communication in many-core processors. However, current silicon-photonic interconnect
designs for many-core processors waste a significant amount of power because (a) lasers are always on, even during
periods of interconnect inactivity, and (b) microring resonators employ heaters which consume a significant amount of
power just to overcome thermal variations and maintain communication on the photonic links, especially in a 3D-stacked
design. The problem of high laser power consumption is particularly important as lasers typically have very low energy
efficiency, and photonic interconnects often remain underutilized both in scientific computing (compute-intensive execution
phases underutilize the interconnect), and in server computing (servers in Google-scale datacenters have a typical utilization
of less than 30%). We address the high laser power consumption by proposing EcoLaser+, which is a laser control
scheme that saves energy by predicting the interconnect activity and opportunistically turning the on-chip laser off when
possible, and also by scaling the width of the communication link based on a runtime prediction of the expected message
length. Our laser control scheme can save up to 62 - 92% of the laser energy, and improve the energy efficiency of a manycore
processor with negligible performance penalty. We address the high trimming (heating) power consumption of the
microrings by proposing insulation methods that reduce the impact of localized heating induced by highly-active components
on the 3D-stacked logic die.
Paper Details
Date Published: 3 April 2015
PDF: 12 pages
Proc. SPIE 9368, Optical Interconnects XV, 93680T (3 April 2015); doi: 10.1117/12.2080496
Published in SPIE Proceedings Vol. 9368:
Optical Interconnects XV
Henning Schröder; Ray T. Chen, Editor(s)
PDF: 12 pages
Proc. SPIE 9368, Optical Interconnects XV, 93680T (3 April 2015); doi: 10.1117/12.2080496
Show Author Affiliations
Yigit Demir, Northwestern Univ. (United States)
Nikos Hardavellas, Northwestern Univ. (United States)
Published in SPIE Proceedings Vol. 9368:
Optical Interconnects XV
Henning Schröder; Ray T. Chen, Editor(s)
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