  The performance of on-chip communication in the state-of-the-art multi-core
processors that use the traditional electron-ic NoCs has already become
severely energy-constrained. To that end, emerging photonic NoCs (PNoC) are
seen as a po-tential solution to improve the energy-efficiency (performance per
watt) of on-chip communication. However, existing PNoC designs cannot realize
their full potential due to their exces-sive laser power consumption. Prior
works that attempt to improve laser power efficiency in PNoCs do not consider
all key factors that affect the laser power requirement of PNoCs. Therefore,
they cannot yield the desired balance between the reduction in laser power,
achieved performance and energy-efficiency in PNoCs. In this paper, we present
PROTEUS framework that employs rule-based self-adaptation in PNoCs. Our
approach not only reduces the laser power consumption, but also minimizes the
average packet latency by opportunis-tically increasing the communication data
rate in PNoCs, and thus, yields the desired balance between the laser power
re-duction, performance, and energy-efficiency in PNoCs. Our evaluation with
PARSEC benchmarks shows that our PROTEUS framework can achieve up to 24.5% less
laser power consumption, up to 31% less average packet latency, and up to 20%
less energy-per-bit, compared to another laser power management technique from
prior work.
