VLSI placement parameter optimization using deep reinforcement learning

Abstract

The quality of placement is essential in the physical design flow. To achieve PPA goals, a human engineer typically spends a considerable amount of time tuning the multiple settings of a commercial placer (e.g. maximum density, congestion effort, etc.). This paper proposes a deep reinforcement learning (RL) framework to optimize the placement parameters of a commercial EDA tool. We build an autonomous agent that learns to tune parameters optimally without human intervention and domain knowledge, trained solely by RL from self-search. To generalize to unseen netlists, we use a mixture of handcrafted features from graph topology theory along with graph embeddings generated using unsupervised Graph Neural Networks. Our RL algorithms are chosen to overcome the sparsity of data and latency of placement runs. Our trained RL agent achieves up to 11% and 2.5% wirelength improvements on unseen netlists compared with a human engineer and a state-of-the-art tool auto-tuner, in just one placement iteration (20× and 50× less iterations).