Microarchitecture evaluation with floorplanning and interconnect pipelining

ABSTRACT

As microprocessor technology continues to scale into the nanometer regime, recent studies show that interconnect delay will be a limiting factor for performance, and multiple cycles will be necessary to communicate global signals across the chip. Thus, longer interconnects need to be pipelined, and the impact of the extra latency along wires needs to be considered during early micro-architecture design exploration. In this paper, we address this problem and make the following contributions: (1) a oor plan-driven micro-architecture evaluation methodology considering interconnect pipelining at a given target frequency by selectively optimizing architecture level critical paths. (2) use of micro-architecture performance sensitivity models to weight micro-architectural critical paths during oor planning and optimize them for higher performance. (3) a methodology to study the impact of frequency scaling on micro-architecture performance with consideration of interconnect pipelining.For a sample micro-architecture design space, we show that considering interconnect pipelining can increase the estimated performance against a no-wire-pipelining approach between 25% to 45%. We also demonstrate the value of the methodology in exploring the target frequency of the processor.

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