It is well known that optimizations made by traditional logic synthesis tools often correlate poorly with post-layout performance; this is largely a result of interconnect effects only being visible after layout. In this paper, acorrectivemethodology is proposed for timing-driven logic restructuring at the placement level. The approach focuses on a lookup table (LUT)-based field programmable gate arrays. The approach is iterative in nature. In each iteration, using current placement information, the method induces a timing-critical fan-in tree via (temporary) replication. Such trees are then reimplemented where the degrees of freedom include functional decomposition of LUTs, ldquomini-LUTrdquo tree mapping, and physical embedding. A dynamic programming algorithm optimizes over all of these freedoms simultaneously.Allsimple disjoint LUT decompositions (i.e., Ashenhurst style) are encoded in a ldquomini-LUTrdquo tree using choice nodes similar to those in the paper by Lehman At the same time, because embedding is done simultaneously, interconnect delay is directly taken into account. Over multiple iterations, the design is progressively improved. The framework has been implemented, and promising experimental results are reported.

Because early design decisions can have a major long term impact on the performance of a system, early evaluation of the high-level architecture can be an important risk mitigation technique. This paper proposes a technique for predicting the volume of data that will flow across a network in a distributed system. The prediction is based upon anticipated execution of scenarios and can be applied at an extremely early stage of the design. It is driven by requirements specifications and captures dynamic metrics by defining typical usage patterns in terms of scenarios. Scenarios are then mapped to architectural components, and dataflow across inter-partition links is estimated. The feasibility of the approach is demonstrated through an experiment in which predicted metrics are compared to runtime measurements.