Designing optimized pipelined global interconnects: Algorithms and methodology impact

As across-chip wire delays exceed a clock cycle, interconnect pipelining becomes essential. However, the arbitrary insertion of flip-flops can change the differentials of latencies along paths in the circuit, and this can cause the implemented circuit to have a different functionality than was intended by the designer. Although it is possible to use design techniques that maintain the functionality of the circuit, an additional concern is a reduction in the throughput. This may be overcome by careful choices at various stages of design that impact the across-chip wire latencies. This paper surveys the published work on wire-pipelining, describes its impact on circuit as well as system level throughput, and outlines some of the problems to be resolved in formulating a wirepipelining centric strategy for physical design.