10 July 2025 in IEEE Transactions on Computers
Due to the demonstrated superiority, dynamic neural networks (NNs), which adapt their network structures to different inputs, have been recognized as an optimized alternative to conventional static NNs. However, researchers have not explored the implications of dynamic NN on neural processing unit (NPU) architecture design. Consequently, we analyze the characteristics and inefficient sources of executing dynamic NNs on existing hardware. From our analysis, existing NPUs, designed for static NNs, cannot effectively handle the execution of dynamic operator and agent-dependent data loading in dynamic NNs. To this end, we present DNA, an efficient accelerator optimized to deal with the challenges of running general dynamic NNs. Firstly, to improve the execution efficiency of dynamic operators, we propose a transverter-based online scheduling strategy to rapidly generate efficient scheduling for each dynamic operator. Secondly, to mitigate hardware idleness caused by the non-deterministic and agent-dependent data access patterns in dynamic NNs, we propose a novel predictor-based prefetching strategy that achieves effective data preloading with negligible cost. We implemented our accelerator, DNA, by integrating an additional online scheduler into a typical many-core baseline accelerator. According to our evaluation of various dynamic NNs, DNA achieves $3.48\boldsymbol\times$ speedup and $3.03\boldsymbol\times$ energy savings over the baseline accelerator.
21 October 2025 in ACM Transactions on Design Automation of Electronic Systems
Hardware description language (HDL) code designing is a critical component of the chip design process, requiring substantial engineering and time resources. Recent advancements in large language models (LLMs), such as GPT series, have shown promise in automating HDL code generation. However, current LLM-based approaches face significant challenges in meeting real-world hardware design requirements, particularly in handling complex designs and ensuring code correctness. Our evaluations reveal that the functional correctness rate of LLM-generated HDL code significantly decreases as design complexity increases. In this article, we propose the AutoSilicon framework, which aims to scale up the hardware design capability of LLMs. AutoSilicon incorporates an agent system, which (1) allows for the decomposition of large-scale, complex code design tasks into smaller, simpler tasks; (2) provides a compilation and simulation environment that enables LLMs to compile and test each piece of code it generates; and (3) introduces a series of optimization strategies. Experimental results demonstrate that AutoSilicon can scale hardware designs to projects with code equivalent to over 10,000 tokens. In terms of design quality, it further improves the syntax correctness rate and functional correctness rate compared with approaches that do not employ any extensions. For example, compared to directly generating HDL code using GPT-4-turbo, AutoSilicon enhances the syntax correctness rate by an average of 35.8% and improves functional correctness by an average of 35.6%.
17 October 2025 in ACM Transactions on Design Automation of Electronic Systems
Recent advances in large language models (LLMs) have demonstrated significant potential for automated hardware description language (HDL) code generation from high-level specifications. However, two critical challenges limit further progress in this domain: the scarcity of quality Verilog training data and the inability of current approaches to generate RTL code optimized for power, performance, and area (PPA) metrics. This article presents a comprehensive data-centric framework that addresses these limitations through innovations in both pre-fine-tuning data preparation and after-fine-tuning optimization strategies. In the pre-fine-tuning phase, we tackle the data scarcity problem with an automated design-data augmentation framework that generates high-volume, high-quality natural language specifications aligned with corresponding Verilog code and EDA scripts. Our approach creates a complete RTL-level feedback loop by augmenting EDA scripts, RTL code, and EDA tool feedback. In the after-fine-tuning phase, we focus on generating PPA-aware RTL code through a novel search and prompt framework. Our approach implements iterative filtering and selection of LLM-generated Verilog variants while providing high-quality predefined prompts, including composition and interface specifications. To evaluate the effectiveness of our data augmentation method, we fine-tune Llama 2-13B and Llama 2-7B models using the dataset generated by our augmentation framework. The results demonstrate a significant improvement in the Verilog generation tasks with LLMs. Moreover, the accuracy of Verilog generation surpasses that of the current state-of-the-art open-source Verilog generation model, increasing from 58.8% to 70.6% with the same benchmark. Our 13B model has a pass rate improvement compared with GPT-3.5 in Verilog generation and outperforms in EDA script (i.e., SiliconCompiler) generation with only 200 EDA script data. Additionally, to evaluate the effectiveness of the our agent framework, we compare the PPA on the GPT-3.5, where the results show that the agent refined RTL code can have a better quality than the generated RTL code only with GPT-3.5.