Microarchitectural wire management for performance and power in partitioned architectures

Future high-performance billion-transistor processors are likely to employ partitioned architectures to achieve high clock speeds, high parallelism, low design complexity, and low power. In such architectures, inter-partition communication over global wires has a significant impact on overall processor performance and power consumption. VLSI techniques allow a variety of wire implementations, but these wire properties have previously never been exposed to the microarchitecture. This paper advocates global wire management at the microarchitecture level and proposes a heterogeneous interconnect that is comprised of wires with varying latency, bandwidth, and energy characteristics. We propose and evaluate microarchitectural techniques that can exploit such a heterogeneous interconnect to improve performance and reduce energy consumption. These techniques include a novel cache pipeline design, the identification of narrow bit-width operands, the classification of non-critical data, and the detection of interconnect load imbalance. For a dynamically scheduled partitioned architecture, our results demonstrate that the proposed innovations result in up to 11% reductions in overall processor ED², compared to a baseline processor that employs a homogeneous interconnect.