Methods for Accurate Wirelength Estimation of Functional Circuitry in ULSI Chips

An accounting for circuitry type in ULSI chips within the context of the historically-equivalent interpretation of Rent’s rule is needed for an assessment of existing on-chip wirelength distribution models. Although prior assessments of these models have separately considered the e.ects of these two factors (namely, circuitry type and Rent’s rule), there does not exist an assessment for today’s ULSI circuits that takes into account the role of circuitry type within the context of this interpretation of Rent’s memos. Providing an assessment that properly accounts for both factors is needed and is the goal of this paper. The main contributions of this paper are: (1) a method that takes into account both factors for assessments of on-chip wirelength distribution models, and (2) wirelength estimates and model wirelength distributions that show much improved agreement with measurements. This paper presents assessments based on these methods for 100 chip designs in the POWER4 microprocessor. The results presented in this paper show that the wirelength estimates now typically closely approximate the measurements and that the total wirelength estimate for all 100 designs agrees with the measured total wirelength to within 23%.