Towards Design Decisions for Genetic Algorithms in Clock Tree Synthesis

Binary clock tree (BCT) synthesis fundamentally depends on the quality of the process of merging pairs. Selecting the optimal merging nodes is computationally expensive, even using heuristic methods. This paper presents an automated synthesis approach based on genetic algorithms (GA), that reduces the search effort for feasible node pair selection. Insights and best practices are presented for using GA processes for generating BCTs that evolve over time. BCTs synthesized with this GA approach are demonstrated experimentally with HSPICE simulations. Furthermore, the impact of utilizing a human-in-the-loop in this GA process for merging pair selection is analyzed methodically. The outcome is a best-practices approach towards automating the synthesis of BCTs based on the proposed GA approach.