Placement for very-large-scale integrated (VLSI) circuits is one of the most important steps for design closure. We propose a novel GPU-accelerated placement framework DREAMPlace, by casting the analytical placement problem equivalently to training a neural network. Implemented on top of a widely-adopted deep learning toolkit PyTorch, with customized key kernels for wirelength and density computations, DREAMPlace can achieve around 40× speedup in global placement without quality degradation compared to the state-of-the-art multi-threaded placer RePlAce. We believe this work shall open up new directions for revisiting classical EDA problems with advancements in AI hardware and software.
The past two decades have witnessed the stagnation of the clock speed of microprocessors followed by the recent faltering of Moore’s law as nanofabrication technology approaches its unavoidable physical limit. Vigorous efforts from various research areas have been made to develop power-efficient and ultrafast computing machines in this post-Moore’s law era. With its unique capacity to integrate complex electro-optic circuits on a single chip, integrated photonics has revolutionized the interconnects and has shown its striking potential in optical computing. Here, we propose an electronic-photonic computing architecture for a wavelength division multiplexing-based electronic-photonic arithmetic logic unit, which disentangles the exponential relationship between power and clock rate, leading to an enhancement in computation speed and power efficiency as compared to the state-of-the-art transistors-based circuits. We experimentally demonstrate its practicality by implementing a 4-bit arithmetic logic unit consisting of 8 high-speed microdisk modulators and operating at 20 GHz. This approach paves the way to future power-saving and high-speed electronic-photonic computing circuits.
In recent decades, the demand for computational power has surged, particularly with the rapid expansion of artificial intelligence (AI). As we navigate the post-Moore's law era, the limitations of traditional electrical digital computing, including process bottlenecks and power consumption issues, are propelling the search for alternative computing paradigms. Among various emerging technologies, integrated photonics stands out as a promising solution for next-generation high-performance computing, thanks to the inherent advantages of light, such as low latency, high bandwidth, and unique multiplexing techniques. Furthermore, the progress in photonic integrated circuits (PICs), which are equipped with abundant photoelectronic components, positions photonic-electronic integrated circuits as a viable solution for high-performance computing and hardware AI accelerators. In this review, we survey recent advancements in both PIC-based digital and analog computing for AI, exploring the principal benefits and obstacles of implementation. Additionally, we propose a comprehensive analysis of photonic AI from the perspectives of hardware implementation, accelerator architecture, and software-hardware co-design. In the end, acknowledging the existing challenges, we underscore potential strategies for overcoming these issues and offer insights into the future drivers for optical computing.
4 February 2020 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Placement is an important step in modern very-large-scale integrated (VLSI) designs. Detailed placement is a placement refining procedure intensively called throughout the design flow, thus its efficiency has a vital impact on design closure. However, since most detailed placement techniques are inherently greedy and sequential, they are generally difficult to parallelize. In this work, we present a concurrent detailed placement framework, ABCDPlace, exploiting multithreading and GPU acceleration. We propose batch-based concurrent algorithms for widely-adopted sequential detailed placement techniques, such as independent set matching, global swap, and local reordering. Experimental results demonstrate that ABCDPlace can achieve 2×-5× faster runtime than sequential implementations with multi-threaded CPU and over 10× with GPU on ISPD 2005 contest benchmarks without quality degradation. On larger industrial benchmarks, we show more than 16× speedup with GPU over the state-of-the-art sequential detailed placer. ABCDPlace finishes the detailed placement of a 10-million-cell industrial design in one minute.
29 September 2020 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
As a promising neuromorphic framework, the optical neural network (ONN) demonstrates ultra-high inference speed with low energy consumption. However, the previous ONN architectures have high area overhead which limits their practicality. In this paper, we propose an areaefficient ONN architecture based on structured neural networks, leveraging optical fast Fourier transform for efficient computation. A two-phase software training flow with structured pruning is proposed to further reduce the optical component utilization. Experimental results demonstrate that the proposed architecture can achieve 2.2 3.7× area cost improvement compared with the previous singular value decompositionbased architecture with comparable inference accuracy. A novel optical microdisk-based convolutional neural network architecture with joint learnability is proposed as an extension to move beyond Fourier transform and multi-layer perception, enabling hardware-aware ONN design space exploration with lower area cost, higher power efficiency, and better noiserobustness.
Neutral atom arrays, particularly the reconfigurable field programmable qubit arrays (FPQA) with atom movement, show strong promise for quantum computing. FPQA has a dynamic qubit connectivity, facilitating cost-effective execution of long-range gates, but it also poses new challenges in the compilation. Inspired by the FPGA compilation strategy, we develop a router, Q-Pilot, that leverages flying ancillas to implement 2-Q gates between data qubits mapped to fixed atoms. Equipped with domain-specific routing techniques, Q-Pilot achieves 1.4×, 27.7×, and 6.7× reductions in circuit depth for 100-qubit random, quantum simulation, and QAOA circuits, respectively, compared to alternative fixed atom array architectures.