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The Power of Graph Signal Processing for Chip Placement Acceleration

Liu, Yiting, Zhou, Hai, Wang, Jia, Yang, Fan, Zeng, Xuan, Shang, Li

arXiv.org Artificial Intelligence

Placement is a critical task with high computation complexity in VLSI physical design. Modern analytical placers formulate the placement objective as a nonlinear optimization task, which suffers a long iteration time. To accelerate and enhance the placement process, recent studies have turned to deep learning-based approaches, particularly leveraging graph convolution networks (GCNs). However, learning-based placers require time- and data-consuming model training due to the complexity of circuit placement that involves large-scale cells and design-specific graph statistics. This paper proposes GiFt, a parameter-free technique for accelerating placement, rooted in graph signal processing. GiFt excels at capturing multi-resolution smooth signals of circuit graphs to generate optimized placement solutions without the need for time-consuming model training, and meanwhile significantly reduces the number of iterations required by analytical placers. Experimental results show that GiFt significantly improving placement efficiency, while achieving competitive or superior performance compared to state-of-the-art placers. In particular, compared to DREAMPlace, the recently proposed GPU-accelerated analytical placer, GF-Placer improves total runtime over 45%.


GOALPlace: Begin with the End in Mind

Agnesina, Anthony, Liang, Rongjian, Pradipta, Geraldo, Rajaram, Anand, Ren, Haoxing

arXiv.org Artificial Intelligence

Co-optimizing placement with congestion is integral to achieving high-quality designs. This paper presents GOALPlace, a new learning-based general approach to improving placement congestion by controlling cell density. Our method efficiently learns from an EDA tool's post-route optimized results and uses an empirical Bayes technique to adapt this goal/target to a specific placer's solutions, effectively beginning with the end in mind. It enhances correlation with the long-running heuristics of the tool's router and timing-opt engine -- while solving placement globally without expensive incremental congestion estimation and mitigation methods. A statistical analysis with a new hierarchical netlist clustering establishes the importance of density and the potential for an adequate cell density target across placements. Our experiments show that our method, integrated as a demonstration inside an academic GPU-accelerated global placer, consistently produces macro and standard cell placements of superior or comparable quality to commercial tools. Our empirical Bayes methodology also allows a substantial quality improvement over state-of-the-art academic mixed-size placers, achieving up to 10x fewer design rule check (DRC) violations, a 5% decrease in wirelength, and a 30% and 60% reduction in worst and total negative slack (WNS/TNS).


DG-RePlAce: A Dataflow-Driven GPU-Accelerated Analytical Global Placement Framework for Machine Learning Accelerators

Kahng, Andrew B., Wang, Zhiang

arXiv.org Artificial Intelligence

Global placement is a fundamental step in VLSI physical design. The wide use of 2D processing element (PE) arrays in machine learning accelerators poses new challenges of scalability and Quality of Results (QoR) for state-of-the-art academic global placers. In this work, we develop DG-RePlAce, a new and fast GPU-accelerated global placement framework built on top of the OpenROAD infrastructure, which exploits the inherent dataflow and datapath structures of machine learning accelerators. Experimental results with a variety of machine learning accelerators using a commercial 12nm enablement show that, compared with RePlAce (DREAMPlace), our approach achieves an average reduction in routed wirelength by 10% (7%) and total negative slack (TNS) by 31% (34%), with faster global placement and on-par total runtimes relative to DREAMPlace. Empirical studies on the TILOS MacroPlacement Benchmarks further demonstrate that post-route improvements over RePlAce and DREAMPlace may reach beyond the motivating application to machine learning accelerators.


Toward Reinforcement Learning-based Rectilinear Macro Placement Under Human Constraints

Le, Tuyen P., Nguyen, Hieu T., Baek, Seungyeol, Kim, Taeyoun, Lee, Jungwoo, Kim, Seongjung, Kim, Hyunjin, Jung, Misu, Kim, Daehoon, Lee, Seokyong, Choi, Daewoo

arXiv.org Artificial Intelligence

Macro placement is a critical phase in chip design, which becomes more intricate when involving general rectilinear macros and layout areas. Furthermore, macro placement that incorporates human-like constraints, such as design hierarchy and peripheral bias, has the potential to significantly reduce the amount of additional manual labor required from designers. This study proposes a methodology that leverages an approach suggested by Google's Circuit Training (G-CT) to provide a learning-based macro placer that not only supports placing rectilinear cases, but also adheres to crucial human-like design principles. Our experimental results demonstrate the effectiveness of our framework in achieving power-performance-area (PPA) metrics and in obtaining placements of high quality, comparable to those produced with human intervention. Additionally, our methodology shows potential as a generalized model to address diverse macro shapes and layout areas.


Location analytics company Placer.ai nabs $100M to generate insights from foot traffic

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Placer.ai, a location analytics platform that serves companies with data around consumer foot traffic, has raised $100 million in a series C round of funding, valuing the company at $1 billion. The location intelligence industry was pegged as a $12 billion market last year, a figure that's predicted to more than double in the coming years as businesses leverage big data insights to improve their bottom line. For example, businesses can glean accurate foot traffic counts and "dwell time," allowing them to filter by time and day as well as customer segments. This can be useful for understanding how special promotions, events, or holidays impact trade. Or they can discover what Placer.ai


On Joint Learning for Solving Placement and Routing in Chip Design

Cheng, Ruoyu, Yan, Junchi

arXiv.org Artificial Intelligence

For its advantage in GPU acceleration and less dependency on human experts, machine learning has been an emerging tool for solving the placement and routing problems, as two critical steps in modern chip design flow. Being still in its early stage, there are fundamental issues: scalability, reward design, and end-to-end learning paradigm etc. To achieve end-to-end placement learning, we first propose a joint learning method termed by DeepPlace for the placement of macros and standard cells, by the integration of reinforcement learning with a gradient based optimization scheme. To further bridge the placement with the subsequent routing task, we also develop a joint learning approach via reinforcement learning to fulfill both macro placement and routing, which is called DeepPR. One key design in our (reinforcement) learning paradigm involves a multi-view embedding model to encode both global graph level and local node level information of the input macros. Moreover, the random network distillation is devised to encourage exploration. Experiments on public chip design benchmarks show that our method can effectively learn from experience and also provides intermediate placement for the post standard cell placement, within few hours for training.


Placement in Integrated Circuits using Cyclic Reinforcement Learning and Simulated Annealing

Vashisht, Dhruv, Rampal, Harshit, Liao, Haiguang, Lu, Yang, Shanbhag, Devika, Fallon, Elias, Kara, Levent Burak

arXiv.org Artificial Intelligence

Physical design and production of Integrated Circuits (IC) is becoming increasingly more challenging as the sophistication in IC technology is steadily increasing. Placement has been one of the most critical steps in IC physical design. Through decades of research, partition-based, analytical-based and annealing-based placers have been enriching the placement solution toolbox. However, open challenges including long run time and lack of ability to generalize continue to restrict wider applications of existing placement tools. We devise a learning-based placement tool based on cyclic application of Reinforcement Learning (RL) and Simulated Annealing (SA) by leveraging the advancement of RL. Results show that the RL module is able to provide a better initialization for SA and thus leads to a better final placement design. Compared to other recent learning-based placers, our method is majorly different with its combination of RL and SA. It leverages the RL model's ability to quickly get a good rough solution after training and the heuristic's ability to realize greedy improvements in the solution.


Placer.ai raises $12M to expand location data services

#artificialintelligence

Placer.ai is among the companies seeking to expand in the high-growth industry of collecting location data from mobile consumers, a practice that has alarmed privacy advocates but continues to draw interest from investors, as this news shows. Spending on location analytics is expected to grow to $15 billion by 2023 from $8.35 billion in 2017, Placer.ai said in a study cited by Bloomberg. These businesses can use the information to identify where to rent or buy properties, or to measure the effect of advertising campaigns on consumer behavior such as store visits. In addition to helping businesses identify where to rent properties in areas of high foot traffic, real-time location data can help to boost the effectiveness of ad campaigns, according to a report last year by location data provider Factual. Location-based marketing, which Martin Sorrell, former CEO of ad-holding giant WPP, once described as the "holy grail" for advertising, reaches consumers when they're most ready to shop, dine out or visit an entertainment venue.