VLDB 2026 Research / reviewers in the wild / expert
Vidya A. Chhabria
dblp:240/0882 · also Vidya Ashok Chhabria
· DBLP profile ↗
34ranked-venue papers
12as first author
32since 2021 · last 2026
0000-0002-3273-0724ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Systems, architecture and hardware · 34 · 12 first-author · 32 since 2021Software engineering, systems software and programming languages · 2 · 1 first-author · 2 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | DALI-PD: Diffusion-based Synthetic Layout Heatmap Generation for ML in Physical DesignabstractMachine learning (ML) has demonstrated significant promise in various physical design (PD) tasks. However, model generalizability remains limited by the availability of high-quality, largescale training datasets. Creating such datasets is often computationally expensive and constrained by IP. While very few public datasets are available, they are typically static, slow to generate, and require frequent updates. To address these limitations, we present DALI-PD, a scalable framework for generating synthetic layout heatmaps to accelerate ML in PD research. DALI-PD uses a diffusion model to generate diverse layout heatmaps via fast inference in seconds. The heatmaps include power, IR drop, congestion, macro placement, and cell density maps. Using DALI-PD, we created a dataset comprising over 20,000 layout configurations with varying macro counts and placements. These heatmaps closely resemble real layouts and improve ML accuracy on downstream ML tasks such as IR drop or congestion prediction. Bing-Yue Wu, Vidya A. Chhabria |
ASP-DAC | 2 |
| 2026 | MIMIC: Machine Intelligence for Scalable Generation of Synthetic Timing Cone DatasetsabstractMany machine learning (ML)-based approaches have been proposed to predict and optimize timing. However, the effectiveness of these techniques is often limited by the lack of large-scale, diverse, and realistic datasets-particularly those that reflect the structural and timing complexities of industry-scale designs. In this work, we introduce MIMIC (Machine intelligence for scalable generation of synthetic timing cone datasets), a methodology for generating high-quality synthetic timing cones that mimic real circuit netlist topologies and timing characteristics. The framework synthesizes a diverse dataset using a three-stage ML pipeline: (1) timing cone shape generation, (2) node type prediction for technology mapping, and (3) edge prediction to model internal cone connectivity. MIMIC produces synthetic yet realistic timing cones for a large-scale netlist within a few minutes. We evaluate the dataset using quantitative statistical EDA and ML world metrics for realism and structural diversity. We also demonstrate the generalizability of the MIMIC dataset for an ML-based timing prediction task. Vinodh Kumar Ramasamy, Juan Arturo Garza, Taylor Hannan, Mahesh Sharma, Vidya A. Chhabria |
ASP-DAC | 7 |
| 2026 | Focus Session: Large Language Models in Physical Design: From Data Generation to Intelligent Agents
Bing-Yue Wu, Atmadip Dey, Austin Rovinski, Vidya A. Chhabria |
DATE | 4 |
| 2025 | Invited: EDA for Heterogeneous IntegrationabstractThe advent of heterogeneous integration (HI) places new demands on EDA tooling. Building large systems requires (1) methods for chiplet disaggregation that map the system to smaller chiplets, working in conjunction with system-technology co-optimization to determine the right design decisions that optimize computation and communication, together with the choice of substrate and chiplet technologies; (2) multiphysics and multiscale analyses that incorporate thermomechanical aspects into performance analysis, ranging from fast machine-learningdriven analyses in early stages to signoff-quality multiphysics-based analysis; (3) physical design techniques for placing and routing chiplets and embedded active/passive elements on and within the substrate, including the design of thermal and power delivery solutions; and (4) underlying infrastructure required to facilitate HI-based design, including the design and characterization of chiplet libraries and the establishment of data formats and standards. This paper overviews these issues and lays out a set of EDA needs for HI designs. Emad Haque, Pragnya Sudershan Nalla, Chetal Choppali Sudarshan, Divya Yogi, Chaitali Chakrabarti, Vidya A. Chhabria, Ramesh Harjani, Jeff Zhang 0001, Sachin S. Sapatnekar |
DAC | 7 |
| 2025 | CarbonSet: A Dataset to Analyze Trends and Benchmark the Sustainability of CPUs and GPUs
Jiajun Hu, Chetan Choppali Sudarshan, Maxwell Clifford, Vidya A. Chhabria, Aman Arora 0001 |
ACM Great Lakes Symposium on VLSI | 4 |
| 2025 | Invited: IEEE DATC RDF-2025: Enabling an EDA Research EcosystemabstractOver the past year, IEEE CEDA DATC has continued to improve the DATC Robust Design Flow (RDF) while continuing to expand initiatives that advance open infrastructures and culture changes, serving the global community of EDA researchers and users. This invited paper focuses on three highlights: (1) establishment of an accessible, "contrib-like" GitHub resource that provides a more accessible environment for OpenROAD- and OpenROAD-flow-scripts-based research works; (2) the first-ever permission mechanism and benchmarking results for a commercial EDA P&R tool, published with permissions developed with the tool vendor (Siemens EDA); and (3) efforts that support a nascent "ML EDA Commons". The paper also provides brief reviews of the past year’s RDF developments and roadmap updates. Vidya A. Chhabria, Amur Ghose, Vikram Gopalakrishnan, Andrew B. Kahng, Sayak Kundu, Yiting Liu 0002, Zhiang Wang, Bing-Yue Wu |
ICCAD | 1 |
| 2025 | Adaptive Graph Learning for Efficient Thermal Analysis of Multi-Stacking Chiplet Systems under Interface VariationsabstractEfficient thermal analysis is critical for ensuring the reliability and performance of modern integrated circuits, particularly in multi-stacking technologies. Traditional thermal analysis methods rely on numerical solutions of partial differential equations (PDEs), which are computationally expensive. This paper introduces a fast thermal framework that synergizes a graph neural network (GNN), hybrid with finite element methods (FEM), to accelerate thermal predictions for a wide range of 2.5D/3D design configurations. Our graph neural network architecture is inherently scalable, accommodating various design sizes. Furthermore, it is able to incorporate additional trainable nodes to be adaptive to new temperature profiles under realistic defect conditions during the assembly process. Validated against fine-grained numerical solutions and real post-silicon thermal imaging data, the proposed framework achieves an average mean absolute percentage error (MAPE) of 0.05%. It completes thermal simulation within a few hundred milliseconds, yielding a speedup of over 1000× compared to conventional steady-state finite difference method (FDM) solvers. Moreover, our method exhibits robust adaptability to previously unseen process and material variations without the need for retraining. Ziyao Yang, Jingbo Sun 0003, Vidya A. Chhabria, Yu Cao 0001 |
ICCAD | 3 |
| 2025 | Toward Lifelong-Sustainable Electronic-Photonic AI Systems via Extreme Efficiency, Reconfigurability, and RobustnessabstractThe relentless growth of large-scale artificial intelligence (AI) has created unprecedented demand for computational power, straining the energy, bandwidth, and scaling limits of conventional electronic platforms. Electronic-photonic integrated circuits (EPICs) have emerged as a compelling platform for nextgeneration AI systems, offering inherent advantages in ultra-high bandwidth, low latency, and energy efficiency for computing and interconnection. Beyond performance, EPICs also hold unique promises for sustainability. Fabricated in relaxed process nodes with fewer metal layers and lower defect densities, photonic devices naturally reduce embodied carbon footprint (CFP) compared to advanced digital electronic integrated circuits, while delivering orders-of-magnitude higher computing performance and interconnect bandwidth. To further advance the sustainability of photonic AI systems, we explore how electronic-photonic design automation (EPDA) and cross-layer co-design methodologies can amplify these inherent benefits. We present how advanced EPDA tools enable more compact layout generation, reducing both chip area and metal layer usage. We will also demonstrate how cross-layer device-circuit-architecture co-design unlocks new sustainability gains for photonic hardware: ultracompact photonic circuit designs that minimize chip area cost, reconfigurable hardware topology that adapts to evolving AI workloads, and intelligent resilience mechanisms that prolong lifetime by tolerating variations and faults. By uniting intrinsic photonic efficiency with EPDA- and co-design-driven gains in area efficiency, reconfigurability, and robustness, we outline a vision for lifelong-sustainable electronic-photonic AI systems. This perspective highlights how EPIC AI systems can simultaneously meet the performance demands of modern AI and the urgent imperative for sustainable computing. Ziang Yin, Hongjian Zhou, Chetan Choppali Sudarshan, Vidya A. Chhabria, Jiaqi Gu 0002 |
ICCD | 4 |
| 2025 | Invited: Toward an ML EDA Commons: Establishing Standards, Accessibility, and Reproducibility in ML-driven EDA ResearchabstractMachine learning (ML) is transforming electronic design automation (EDA), offering innovative solutions for designing and optimizing integrated circuits (ICs). However, the field faces significant challenges in standardization, accessibility, and reproducibility, limiting the impact of ML-driven EDA (ML EDA) research. To address these barriers, this paper presents a vision for an ML EDA Commons, a collaborative open ecosystem designed to unify the community and drive progress through establishing standards, shared resources, and stakeholder-based governance. The ML EDA Commons focuses on three objectives: (1) Maturing existing EDA infrastructure to support ML EDA research; (2) Establishing standards for benchmarks, metrics, and data quality and formats for consistent evaluation via governance that includes key stakeholders; and (3) Improving accessibility and reproducibility by providing open datasets, tools, models, and workflows with cloud computing resources, to lower barriers to ML EDA research and promote robust research practices via artifact evaluations, canonical evaluators, and integration pipelines. Inspired by successes of ML and MLCommons, the ML EDA Commons aims to catalyze transparency and sustainability in ML EDA research. Vidya A. Chhabria, Jiang Hu 0001, Andrew B. Kahng, Sachin S. Sapatnekar |
ISPD | 1 |
| 2025 | HISIM: Analytical Performance Modeling and Design Space Exploration of 2.5D/3D Integration for AI ComputingabstractMonolithic designs face significant fabrication cost and data movement challenges, especially when executing complex and diverse AI models. Advanced 2.5D/3D packaging promises high bandwidth and connection density to overcome these challenges, yet it also introduces new electro-thermal constraints. This article develops a suite of analytical performance models to enable efficient benchmarking of a 2.5D/3D heterogeneous system for energy-efficient AI computing. These models encompass various performance metrics related to computing units, network-on-chip (NoC), and network-on-package (NoP). The results are summarized into a new tool, HISIM, which is$10^{4} \times $–$10^{6} \times $faster than state-of-the-art AI benchmark tools. Furthermore, HISIM integrates rapid thermal simulation for the 2.5D/3D system, helping shed light on both the potential and limitations of 2.5D/3D heterogeneous integration (HI) on representative AI algorithms. The code of HISIM is available athttps://github.com/mec-UMN/HISIM. Zhenyu Wang 0016, Pragnya Sudershan Nalla, Jingbo Sun 0003, A. Alper Goksoy, Sumit K. Mandal, Jae-sun Seo, Vidya A. Chhabria, Jeff Zhang 0001, Chaitali Chakrabarti, Ümit Y. Ogras, Yu Cao 0001 |
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. | 7 |
| 2025 | An Analytical Solution for Transient Electromigration Stress in Multisegment Straight-line Interconnects Based on a Stress-wave ModelabstractThis work presents an analytical approach for analyzing electromigration (EM) in modern technologies that use copper dual damascene (Cu DD) interconnects. In these technologies, due to design rule and methodology constraints, wires are typically laid out unidirectionally in each metal layer; since EM in Cu DD interconnects do not cross layer boundaries, the problem reduces to one of analyzing EM in multisegment interconnect lines. In contrast with traditional empirical methodologies, our approach is based on physics-based modeling, directly solving the differential equations that model EM-induced stress. This article places a focus on interconnect lines, for reasons described above, and introduces the new concept of boundary reflections of stress flux that ascribes a physical (wave-like) analogy to the transient stress behavior in a finite multisegment line. This framework is used to derive analytical expressions of transient EM stress for lines with any number of segments, which can also be tailored to include the appropriate number of terms for any desired level of accuracy. The approach is applied to both the nucleation phase and the postvoiding phase on large power grid benchmarks. These experiments demonstrate excellent accuracy as compared to accurate numerical solution, as well as linear complexity with the number of segments for evaluating stress at a specified point and time. Mohammad Abdullah Al Shohel, Vidya A. Chhabria, Nestoras E. Evmorfopoulos, Sachin S. Sapatnekar |
ACM Trans. Design Autom. Electr. Syst. | 2 |
| 2024 | Exploiting 2.5D/3D Heterogeneous Integration for AI ComputingabstractThe evolution of AI algorithms has not only revolutionized many application domains, but also posed tremendous challenges on the hardware platform. Advanced packaging technology today, such as 2.5D and 3D interconnection, provides a promising solution to meet the ever-increasing demands of bandwidth, data movement, and system scale in AI computing. This work presents HISIM, a modeling and benchmarking tool for chiplet-based heterogeneous integration. HISIM emphasizes the hierarchical interconnection that connects various chiplets through network-on-package. It further integrates technology roadmap, power/latency prediction, and thermal analysis together to support electro-thermal co-design. Leveraging HISIM with in-memory computing chiplets, we explore the advantages and limitations of 2.5D and 3D heterogenous integration on representative AI algorithms, such as DNNs, transformers, and graph neural networks. Zhenyu Wang 0016, Jingbo Sun 0003, A. Alper Goksoy, Sumit K. Mandal, Yaotian Liu, Jae-sun Seo, Chaitali Chakrabarti, Ümit Y. Ogras, Vidya A. Chhabria, Jeff Zhang 0001, Yu Cao 0001 |
ASPDAC | 9 |
| 2024 | GreenFPGA: Evaluating FPGAs as Environmentally Sustainable Computing SolutionsabstractGrowing global concerns about climate change highlight the need for environmentally sustainable computing. The ecological impact of computing, including operational and embodied, is crucial. Field Programmable Gate Arrays (FPGAs) stand out as promising sustainable computing platforms due to their reconfigurability across various applications. This paper introduces GreenFPGA, a tool estimating the total carbon footprint (CFP) of FPGAs over their lifespan, considering design, manufacturing, reconfigurability, operation, disposal, and recycling. Using GreenFPGA, the paper evaluates scenarios where the ecological benefits of FPGA reconfigurability outweigh operational and embodied carbon costs, positioning FPGAs as an environmentally sustainable choice for hardware acceleration compared to Application-specific integrated circuits (ASICs). Experimental results show that FPGAs have lower CFP than ASICs for multiple low-volume applications or short application lifespans. Chetan Choppali Sudarshan, Aman Arora 0001, Vidya A. Chhabria |
DAC | 3 |
| 2024 | ECO-CHIP: Estimation of Carbon Footprint of Chiplet-based Architectures for Sustainable VLSIabstractDecades of progress in energy-efficient and low-power design have successfully reduced the operational carbon footprint in the semiconductor industry. However, this has led to increased embodied emissions, arising from design, manufacturing, and packaging. While existing research has developed tools to analyze embodied carbon for traditional monolithic systems, these tools do not apply to near-mainstream heterogeneous integration (HI) technologies. HI systems offer significant potential for sustainable computing by minimizing carbon emissions through two key strategies: “reducing” computation by “reusing” pre-designed chiplet IP blocks and adopting hierarchical approaches to system design. The reuse of chiplets across multiple designs, even spanning multiple generations of ICs, can substantially reduce carbon emissions throughout the lifespan. This paper introduces ECO-CHIP, a carbon analysis tool designed to assess the potential of HI systems toward sustainable computing by considering scaling, chip let, and packaging yields, design complexity, and even overheads associated with advanced packaging techniques. Experimental results from ECO-CHIP demonstrate that HI can reduce embodied carbon emissions by up to 30% compared to traditional monolithic systems. ECO-CHIP is integrated with other chiplet simulators and is applied to chiplet disaggregation considering other metrics such as power, area, and cost. ECO-CHIP suggests that HI can pave the way for sustainable computing practices. Chetan Choppali Sudarshan, Nikhil Matkar, Sarma B. K. Vrudhula, Sachin S. Sapatnekar, Vidya A. Chhabria |
HPCA | 5 |
| 2024 | Strengthening the Foundations for IC Physical Design and ML EDA ResearchabstractOver the past year, IEEE CEDA DATC has continued to improve the DATC Robust Design Flow (RDF) while also advancing open infrastructure for research, including machine learning for electronic design automation (ML EDA). The 2024 RDF release includes new standalone and integrated global placement and macro placement engines, as well as a CCS-based delay calculator. Advances in baselines and benchmarks include the addition of new benchmarks for macro placement and logic gate sizing, as well as further efforts to establish calibrations of both optimizations and analyses to aid assessments of research progress in EDA. Additional efforts to promote open and reproducible research include refined proxy research enablements and enhanced ML EDA infrastructure through the development and use of new formats, the release of datasets, and the development of Python APIs in OpenROAD. Vidya A. Chhabria, Vikram Gopalakrishnan, Andrew B. Kahng, Sayak Kundu, Zhiang Wang, Bing-Yue Wu, Dooseok Yoon |
ICCAD | 1 |
| 2024 | Generative Methods in EDA: Innovations in Dataset Generation and EDA Tool AssistantsabstractThe electronic design automation (EDA) community has recently begun recognizing the potential of generative artificial intelligence (AI) in chip design. However, its full potential is not fully exploited due to the limited availability of publicly accessible datasets crucial for advancing research in EDA. This paper highlights the dual role of generative AI; in particular, it showcases (i) BeGAN, the use of a generative AI strategy to create thousands of realistic benchmarks for power grid synthesis and analysis to advance power-related research, and (ii) EDA Corpus---an expert-curated and generative AI-enhanced dataset to serve research and development of EDA tool assistants. These two case studies emphasize the ability of generative methods to create and utilize datasets to advance research and lower the barriers to entry in EDA. Vidya A. Chhabria, Bing-Yue Wu, Utsav Sharma, Kishor Kunal, Austin Rovinski, Sachin S. Sapatnekar |
ICCAD | 1 |
| 2024 | Analyzing the Impact of FinFET Self-Heating on the Performance of RF Power AmplifiersabstractIn FinFET nodes, high transistor power densities in a power amplifier (PA) lead to device self-heating (SH), degrading performance. This study investigates the impact of SH in large PA FinFET arrays. An encoder-decoder network, together with a long short-term memory model, is used for rapid and accurate thermal analysis. This fast analyzer helps better explore design optimizations than conventional computationally-expensive thermal solvers. The work explores methods for mitigating thermal effects in PAs by inserting dummy transistors within the array of active FinFET devices, and shows the impact of duty cycle and frequency on PA performance. Nibedita Karmokar, Sai-Wang Tam, Thanh Viet Dinh, Vidya A. Chhabria, Ramesh Harjani, Sachin S. Sapatnekar |
ICCAD | 4 |
| 2024 | 2024 ICCAD CAD Contest Problem C: Scalable Logic Gate Sizing Using ML Techniques and GPU AccelerationabstractLogic gate sizing plays a vital role in timing optimization, especially as Moore's Law slows, shifting greater responsibility to EDA tools to enhance power, performance, and area (PPA), as these gains are no longer achieved solely through scaling and process advancements. There is an increasing need to push the limits of logic gate sizing to extract every possible improvement in PPA. With recent breakthroughs in machine learning (ML) and the computational power of GPUs, there is significant potential to elevate logic gate sizing algorithms to new heights. This contest aims to advance logic gate sizing and push the boundaries of PPA improvement through innovative EDA tools that leverage machine learning and GPU acceleration. As part of the contest, an infrastructure has been developed to enable ML and GPU-accelerated logic gate sizing algorithms, including the release of benchmarks in both standard EDA and ML-friendly formats, along with examples of incorporating "ML inside" EDA tools through Python APIs. The contest leverages the open-source EDA tool OpenROAD and ML-friendly data representation format, CircuitOps, to lower barriers to entry by providing accessible formats and tools, allowing participants to build on existing software without redundancy. With over 25 teams actively participating, the contest highlights growing interest and potential to push the boundaries of timing optimization. Bing-Yue Wu, Rongjian Liang, Geraldo Pradipta, Anthony Agnesina, Haoxing Ren, Vidya A. Chhabria |
ICCAD | 6 |
| 2024 | ML-INSIGHT: Machine Learning for Inrush Current Prediction and Power Switch Network ImprovementabstractToday's large-scale designs utilize power gating to achieve low power consumption. This strategy involves creating an efficient power switch network that considers both the surge current (inrush) and the time it takes for the domain to wake up (wakeup latency). Optimized design of the power switch network requires an approach that minimizes the inrush current while meeting the wakeup latency specification. However, analyzing the network for inrush is computationally very expensive with large runtimes, particularly for complex networks, making an optimization framework that calls the analysis engine under the hood prohibitively slow. To address this challenge, this paper introduces the use of machine learning (ML) techniques to estimate inrush current. The ML-enabled fast inference for inrush prediction is applied to optimize the power switch network to minimize the inrush current and also meet the wakeup latency constraint. The ML model demonstrates a mean error of 5% compared to SPICE simulations, offering an acceleration of over 50X. Vikram Gopalakrishnan, Bing-Yue Wu, Vidya A. Chhabria |
ISLPED | 3 |
| 2024 | OpenROAD and CircuitOps: Infrastructure for ML EDA Research and EducationabstractTraditional electronic design automation (EDA) techniques struggle to fulfill the stringent efficiency and quick turnaround demands of complex integrated systems. Machine learning (ML) strategies for EDA (“ML EDA”) are pivotal in transforming EDA to address these challenges. However, they encounter significant obstacles due to inadequate infrastructure, ranging from datasets to software interfaces. This paper demonstrates a software infrastructure for ML EDA built on two key technologies: (i) OpenROAD’s Python APIs, and (ii) NVIDIA’s CircuitOps, an EDA data representation format tailored for ML, facilitating ML EDA applications. The paper illustrates three ML EDA examples that utilize the established OpenROAD and CircuitOps infrastructure. Vidya A. Chhabria, Wenjing Jiang, Andrew B. Kahng, Rongjian Liang, Haoxing Ren, Sachin S. Sapatnekar, Bing-Yue Wu |
VTS | 1 |
| 2024 | A Machine Learning Approach to Improving Timing Consistency between Global Route and Detailed RouteabstractDue to the unavailability of routing information in design stages prior to detailed routing (DR), the tasks of timing prediction and optimization pose major challenges. Inaccurate timing prediction wastes design effort, hurts circuit performance, and may lead to design failure. This work focuses on timing prediction after clock tree synthesis and placement legalization, which is the earliest opportunity to time and optimize a “complete” netlist. The article first documents that having “oracle knowledge” of the final post-DR parasitics enables post-global routing (GR) optimization to produce improved final timing outcomes. To bridge the gap between GR-based parasitic and timing estimation and post-DR results during post-GR optimization , machine learning (ML)-based models are proposed, including the use of features for macro blockages for accurate predictions for designs with macros. Based on a set of experimental evaluations, it is demonstrated that these models show higher accuracy than GR-based timing estimation. When used during post-GR optimization, the ML-based models show demonstrable improvements in post-DR circuit performance. The methodology is applied to two different tool flows—OpenROAD and a commercial tool flow—and results on an open-source 45nm bulk and a commercial 12nm FinFET enablement show improvements in post-DR timing slack metrics without increasing congestion. The models are demonstrated to be generalizable to designs generated under different clock period constraints and are robust to training data with small levels of noise. Vidya A. Chhabria, Wenjing Jiang, Andrew B. Kahng, Sachin S. Sapatnekar |
ACM Trans. Design Autom. Electr. Syst. | 1 |
| 2023 | Invited Paper: 2023 ICCAD CAD Contest Problem C: Static IR Drop Estimation Using Machine LearningabstractPower delivery network (PDN) analysis is a critical aspect of the design cycle to ensure the power grid meets the current demands of the chip. Static IR drop simulation, performed as a part of PDN analysis, is crucial to the estimation of the worstcase voltage drop (IR) drop of the chip which in turn determines chip frequency and functionality. Algorithmically, the static IR drop simulation amounts to solving a large system of linear equations with billions of variables and is computationally very expensive with significantly large runtimes. This contest aims at leveraging machine learning (ML) techniques to overcome this challenge. While previous research has introduced ML-based solutions for static IR drop simulation, their performance remains untested on standardized benchmarks, obscuring the true state-of-the-art ML model. The contest releases twenty real circuit (split as ten seen during training and ten as hidden) benchmarks and hundreds of synthetic benchmarks for training ML models to predict IR drop. The synthetic data serves as a training dataset, which can then be fine-tuned using limited real circuit data for accurate predictions on unseen testcases. The goal of the contest is to train novel ML algorithms to perform the prediction with high accuracy, F1 score, and low runtimes. Gana Surya Prakash Kadagala, Vidya A. Chhabria |
ICCAD | 2 |
| 2023 | Invited Paper: CircuitOps: An ML Infrastructure Enabling Generative AI for VLSI Circuit OptimizationabstractAn innovative ML infrastructure named CircuitOps is developed to streamline dataset generation and model inference for various generative AI (GAI)-based circuit optimization tasks. Addressing the challenges of the absence of a shared Intermediate Representation (IR), steep EDA learning curves, and AI-unfriendly data structures, we propose solutions that empower efficient data handling. Our contributions encompass the following: (1) labeled property graphs (LPGs) as IR for flexible netlist representation and efficient parallel processing; (2) tools-agnostic IR generation from standard EDA files; (3) customizable dataset generation facilitated through AI-friendly LPGs; (4) gRPC-based inference deployment. Compared with using Tcl interfaces of EDA design tools, CircuitOps achieves a significant 99× dataset generation speedup and 75K nets per second transfer throughput, validating its effectiveness in optimizing GAI tasks. Rongjian Liang, Anthony Agnesina, Geraldo Pradipta, Vidya A. Chhabria, Haoxing Ren |
ICCAD | 4 |
| 2023 | Frequency-Domain Transient Electromigration Analysis Using Circuit TheoryabstractThe analysis of transient stress buildup in on-chip interconnects due to electromigration (EM) requires the solution of partial differential equations (PDEs) with appropriate boundary conditions, but prior approaches have been computationally expensive. This paper uses a stress-electrical equivalence to map the solution of the system of PDEs for a general multisegment interconnect to an RC network. For tree structures, this system is solved in linear time in the frequency domain using model order reduction (MOR) techniques. We present two MOR approaches: one that is not guaranteed to provide a stable approximant due to the presence of the mass-conservation equation, but empirically does so for a large fraction of testcases; and another that is guaranteed-stable. To achieve a guaranteed-stable solution, the approach approximates the RC circuit in a Krylov space and captures the impact of mass conservation in the form of a mass conservation excitation. However, the latter is observed to be slightly less accurate than the first approach when it does provide a solution. The method demonstrates excellent accuracy against a commercial numerical solver, and is scalable, solving transient EM analysis problems on large power grid interconnect benchmarks. Mohammad Abdullah Al Shohel, Vidya A. Chhabria, Nestoras E. Evmorfopoulos, Sachin S. Sapatnekar |
ICCAD | 2 |
| 2023 | Recent Progress in the Analysis of Electromigration and Stress Migration in Large Multisegment InterconnectsabstractTraditional approaches to analyzing electromigration (EM) in on-chip interconnects are largely driven by semi-empirical models. However, such methods are inexact for the typical multisegment lines that are found in modern integrated circuits. This paper overviews recent advances in analyzing EM in on-chip interconnect structures based on physics-based models that use partial differential equations, with appropriate boundary conditions, to capture the impact of electron-wind and back-stress forces within an interconnect, across multiple wire segments. Methods for both steady-state and transient analysis are presented, highlighting approaches that can solve these problems with a computation time that is linear in the number of wire segments in the interconnect. Nestoras E. Evmorfopoulos, Mohammad Abdullah Al Shohel, Olympia Axelou, Pavlos Stoikos, Vidya A. Chhabria, Sachin S. Sapatnekar |
ISPD | 5 |
| 2023 | Encoder-Decoder Networks for Analyzing Thermal and Power Delivery NetworksabstractPower delivery network (PDN) analysis and thermal analysis are computationally expensive tasks that are essential for successful integrated circuit (IC) design. Algorithmically, both these analyses have similar computational structure and complexity as they involve the solution to a partial differential equation of the same form. This article converts these analyses into image-to-image and sequence-to-sequence translation tasks, which allows leveraging a class of machine learning models with an encoder-decoder–based generative (EDGe) architecture to address the time-intensive nature of these tasks. For PDN analysis, we propose two networks: (i) IREDGe: a full-chip static and dynamic IR drop predictor and (ii) EMEDGe: electromigration (EM) hotspot classifier based on input power, power grid distribution, and power pad distribution patterns. For thermal analysis, we propose ThermEDGe, a full-chip static and dynamic temperature estimator based on input power distribution patterns for thermal analysis. These networks are transferable across designs synthesized within the same technology and packing solution. The networks predict on-chip IR drop, EM hotspot locations, and temperature in milliseconds with negligibly small errors against commercial tools requiring several hours. Vidya A. Chhabria, Vipul Ahuja, Ashwath Prabhu, Nikhil Patil, Palkesh Jain, Sachin S. Sapatnekar |
ACM Trans. Design Autom. Electr. Syst. | 1 |
| 2022 | OpeNPDN: A Neural-Network-Based Framework for Power Delivery Network SynthesisabstractPower delivery network (PDN) design is a nontrivial, time-intensive, and iterative task. Correct PDN design must consider power bumps, currents, blockages, and signal congestion distribution patterns. This work proposes a machine learning-based methodology that employs a set of predefined PDN templates. At the floorplan stage, coarse estimates of current, congestion, macro/blockages, and C4 bump distributions are used to synthesize a grid for early design. At the placement stage, the grid is incrementally refined based on more accurate and fine-grained distributions of current and congestion. At each stage, a convolutional neural network (CNN) selects an appropriate PDN template for each region on the chip, building a safe-by-construction PDN that meets IR drop and electromigration (EM) specifications. The CNN is initially trained using a large synthetically created dataset, following which transfer learning is leveraged to bridge the gap between real-circuit data (with a limited dataset size) and synthetically generated data. On average, the optimization of the PDN frees thousands of routing tracks in congestion-critical regions, when compared to a globally uniform PDN, while staying within the IR drop and EM limits. Vidya A. Chhabria, Sachin S. Sapatnekar |
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. | 1 |
| 2021 | Thermal and IR Drop Analysis Using Convolutional Encoder-Decoder NetworksabstractComputationally expensive temperature and power grid analyses are required during the design cycle to guide IC design. This paper employs encoder-decoder based generative (EDGe) networks to map these analyses to fast and accurate image-to-image and sequence-to-sequence translation tasks. The network takes a power map as input and outputs the temperature or IR drop map. We propose two networks: (i) ThermEDGe: a static and dynamic full-chip temperature estimator and (ii) IREDGe: a full-chip static IR drop predictor based on input power, power grid distribution, and power pad distribution patterns. The models are design-independent and must be trained just once for a particular technology and packaging solution. ThermEDGe and IREDGe are demonstrated to rapidly predict on-chip temperature and IR drop contours in milliseconds (in contrast with commercial tools that require several hours or more) and provide an average error of 0.6% and 0.008% respectively. Vidya A. Chhabria, Vipul Ahuja, Ashwath Prabhu, Nikhil Patil, Palkesh Jain, Sachin S. Sapatnekar |
ASP-DAC | 1 |
| 2021 | A New, Computationally Efficient "Blech Criterion" for Immortality in General InterconnectsabstractTraditional methodologies for analyzing electromigration (EM) in VLSI circuits first filter immortal wires using Blech’s criterion, and then perform detailed EM analysis on the remaining wires. However, Blech’s criterion was designed for two-terminal wires and does not extend to general structures. This paper demonstrates a first-principles-based solution technique for determining the steady-state stress at all the nodes of a general interconnect structure, and develops an immortality test whose complexity is linear in the number of edges of an interconnect structure. The proposed model is applied to a variety of structures. The method is shown to match well with results from numerical solvers, to be scalable to large structures. Mohammad Abdullah Al Shohel, Vidya A. Chhabria, Sachin S. Sapatnekar |
DAC | 2 |
| 2021 | MAVIREC: ML-Aided Vectored IR-Drop Estimation and ClassificationabstractVectored IR drop analysis is a critical step in chip signoff that checks the power integrity of an on-chip power delivery network. Due to the prohibitive runtimes of dynamic IR drop analysis, the large number of test patterns must be whittled down to a small subset of worst-case IR vectors. Unlike the traditional slow heuristic method that select a few vectors with incomplete coverage, MAVIREC uses machine learning techniques -- 3D convolutions and regression-like layers -- for accurately recommending a larger subset of test patterns that exercise worst-case scenarios. In under 30 minutes, MAVIREC profiles 100K-cycle vectors and provides better coverage than a state-of-the-art industrial flow. Further, MAVIREC's IR drop predictor shows 10x speedup with under 4mV RMSE relative to an industrial flow. Vidya A. Chhabria, Yanqing Zhang 0002, Haoxing Ren, Ben Keller, Brucek Khailany, Sachin S. Sapatnekar |
DATE | 1 |
| 2021 | BeGAN: Power Grid Benchmark Generation Using a Process-portable GAN-based MethodologyabstractEvaluating CAD solutions to physical implementation problems has been extremely challenging due to the unavailability of modern benchmarks in the public domain. This work aims to address this challenge by proposing a process-portable machine learning (ML)-based methodology for synthesizing synthetic power delivery network (PDN) benchmarks that obfuscate intellectual property information. In particular, the proposed approach leverages generative adversarial networks (GAN) and transfer learning techniques to create realistic PDN benchmarks from a small set of available real circuit data. BeGAN generates thousands of PDN benchmarks with significant histogram correlation (p-value ≤ 0.05) demonstrating its realism and an average L1 Norm of more than 7.1 %, highlighting its IP obfuscation capabilities. The original and thousands of ML-generated synthetic PDN benchmarks for four different open-source technologies are released in the public domain to advance research in this field. Vidya A. Chhabria, Kishor Kunal, Masoud Zabihi, Sachin S. Sapatnekar |
ICCAD | 1 |
| 2021 | Analytical Modeling of Transient Electromigration Stress based on Boundary ReflectionsabstractTraditional methods that test for electromigration (EM) failure in multisegment interconnects, over the lifespan of an IC, are based on the use of the Blech criterion, followed by Black's equation. Such methods analyze each segment independently, but are well known to be inaccurate due to stress buildup over multiple segments. This paper introduces the new concept of boundary reflections of stress flow that ascribes a physical (wave-like) interpretation to the transient stress behavior in a finite multisegment line. This can provide a framework for deriving analytical expressions of transient EM stress for lines with any number of segments, which can also be tailored to include the appropriate number of terms for any desired level of accuracy. The proposed method is shown to have excellent accuracy, through evaluations against the FEM solver COMSOL, as well as scalability, through its application on large power grid benchmarks. Mohammad Abdullah Al Shohel, Vidya A. Chhabria, Nestoras E. Evmorfopoulos, Sachin S. Sapatnekar |
ICCAD | 2 |
| 2020 | Template-based PDN Synthesis in Floorplan and Placement Using Classifier and CNN TechniquesabstractDesigning an optimal power delivery network (PDN) is a time-intensive task that involves many iterations. This paper proposes a methodology that employs a library of predesigned, stitchable templates, and uses machine learning (ML) to rapidly build a PDN with region-wise uniform pitches based on these templates. Our methodology is applicable at both the floorplan and placement stages of physical implementation. (i) At the floorplan stage, we synthesize an optimized PDN based on early estimates of current and congestion, using a simple multilayer perceptron classifier. (ii) At the placement stage, we incrementally optimize an existing PDN based on more detailed congestion and current distributions, using a convolution neural network. At each stage, the neural network builds a safe-by-construction PDN that meets IR drop and electromigration (EM) specifications. On average, the optimization of the PDN brings an extra 3% of routing resources, which corresponds to a thousands of routing tracks in congestion-critical regions, when compared to a globally uniform PDN, while staying within the IR drop and EM limits. Vidya A. Chhabria, Andrew B. Kahng, Uday Mallappa, Sachin S. Sapatnekar, Bangqi Xu |
ASP-DAC | 1 |
| 2019 | Toward an Open-Source Digital Flow: First Learnings from the OpenROAD ProjectabstractWe describe the planned Alpha release of OpenROAD, an open-source end-to-end silicon compiler. OpenROAD will help realize the goal of "democratization of hardware design", by reducing cost, expertise, schedule and risk barriers that confront system designers today. The development of open-source, self-driving design tools is in and of itself a "moon shot" with numerous technical and cultural challenges. The open-source flow incorporates a compatible open-source set of tools that span logic synthesis, floorplanning, placement, clock tree synthesis, global routing and detailed routing. The flow also incorporates analysis and support tools for static timing analysis, parasitic extraction, power integrity analysis, and cloud deployment. We also note several observed challenges, or "lessons learned", with respect to development of open-source EDA tools and flows. Tutu Ajayi, Vidya A. Chhabria, Mateus Fogaça, Soheil Hashemi, Abdelrahman Hosny, Andrew B. Kahng, Jeongsup Lee, Uday Mallappa, Marina Neseem, Geraldo Pradipta, Sherief Reda, Mehdi Saligane, Sachin S. Sapatnekar, Carl Sechen, Mohamed Shalan, William Swartz, Lutong Wang, Zhehong Wang, Mingyu Woo, Bangqi Xu |
DAC | 2 |