Energy-Efficient Encoding for High-Performance Buses with Staggered Repeaters

High-performance buses often use staggered repeaters to mitigate the adverse impact on latency of worst-case capacitive crosstalk between adjacent wires by exploiting the data-dependent nature of crosstalk. An undesirable side effect of staggered repeaters is that they may increase the overall energy of a bus carrying highly correlated traffic associated with real-world benchmarks. In this paper, we introduce an energy model for a staggered-repeater bus (SRB) configuration and propose a low-power dynamic encoding scheme that yields average bus energy reductions for an SRB in excess of 28% and 26% for data and instruction traffic, respectively, for SPEC CPU2k benchmarks.