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Friday 28 August

Hardware Architecture

CAGE: Regime-Aware Algorithm Engineering for Coverage Optimization

Coverage-selection policies that optimize the same monotone objective can occupy different quality-runtime frontiers as workload scale, budget, repetition horizon, and execution substrate change. CAGE is a regime-aware algorithm-engineering framework that holds coverage semantics fixed through a shared bitset execution substrate and studies how the nondominated strategy set changes under controlled operating conditions. We separate intrinsic workload descriptors from measured strategy response, represent each condition by its empirical Pareto set, and identify regime transitions from changes in Pareto membership or statistically supported crossovers. Across Defects4J, Epinions, a BWSN-inspired time-to-detection workload, repeated selection, and an embedded RV32 realization, we observe distinct transitions. At a 5% budget, one-exchange refinement adds 27 Chart lines at 11.3x baseline median runtime, whereas deeper search adds five Time lines at roughly 715x. On Math, CP-SAT confirms full-universe optimality at 20% and 40% and residual lower-budget headroom. Persistent preprocessing reuse first achieves confidence-interval-supported speedup at horizon 20 and reaches 1.442x at horizon 100. ModelSim shows a separate bitset-width crossover. The results demonstrate that strategy nondominance is workload- and condition-dependent, supporting regime-aware algorithm engineering rather than a universal policy ranking.
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Hardware Architecture

Certified Bank-Aware Fast-Path Coverage for Hardware-Constrained NDN Forwarding Lookup

Named Data Networking (NDN) replaces address-based forwarding with longest-prefix lookup over variable-length hierarchical names, creating a difficult fit with bounded hardware fast paths. We formulate this problem as certified fast-path coverage. An offline mapper selects a prefix-closed set of parser-visible trie nodes and a separate set of action-equivalence certificates under a shared budget. A certificate relates a selected shallow FIB prefix to a deeper true-LPM class with the same forwarding action; applying the shortcut requires a sound class guard, while uncertain traffic falls back to an exact path. We present BPC-Greedy, a certificate-aware placement heuristic, and BPC-Portfolio, a multi-strategy wrapper spanning exact-heavy, repair-based, and shallow-shortcut constructions. The formulation exposes a tree-closure knapsack structure for prefix placement, exact top-k certificate selection for a fixed selected set under uniform certificate cost, and a separate bank-feasibility layer. On a synthetic parser-depth sweep and a 50k replay of public NDN testbed names under a reproducible synthetic forwarding-action snapshot, modeled certified coverage increases from 46.48% for the best exact-prefix-only bank-aware baseline to 64.06% at total budget M=48. These results characterize placement opportunity under the stated model: the evaluator uses the known true LPM as an oracle-style guard, certificate-table bank traffic is not modeled, and no claim is made about synthesized latency, area, or throughput.
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Hardware Architecture · Cross-listed from cs.SE

Physics-Direct FPGA Tooth-Contact Computation for Deterministic Gear Digital Twins

Gear digital twins, hardware-in-the-loop rigs, and active vibration control close a loop around the instantaneous tooth-contact state, demanding a solver that is real-time, deterministic, and embeddable – properties that loaded tooth contact analysis (LTCA), a data-dependent linear complementarity problem (LCP) costing seconds per mesh phase in fp64, structurally lacks; learned surrogates infer fast but spend one full LTCA solve per training sample and offer no guarantee beyond their training envelope. We instead compress the closed-form contact physics – contact-point localization, principal-curvature extraction, and the elliptical Hertz solution – directly into a branch-free fixed-point FPGA datapath, termed physics-direct, realized through the fully open-source openXC7 flow (no vendor tools, no floating-point IP) and validated on retired XC7K480T silicon. Four SoCs – geometry, Hertz, and two fused paths – pass bit-exact JTAG readback against a golden model. The on-chip preview tracks LCP body pressure to within -22% and loaded transmission error (LTE) peak-to-peak to -19%, preserving the exact $W^{1/3}$ law; with zero training it extrapolates in load more accurately than a trained network (18.9% versus 20.3%). Latency is a compile-time constant ($\sigma = 0$ jitter), and the DSP-bound geometry kernel saturates the fabric near 63 lanes. Physics-direct is an interpretable, deterministic alternative to neural surrogacy for embedded tooth-contact estimation.
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Hardware Architecture

Neuromorphic architectures as numerical solvers for computational neuroscience

Neuromorphic computing is closely associated with spiking neuronal networks. However, an alternative class of so-called "rate-based" models arising from computational neuroscience and machine learning forgoes spiking interactions and instead relies on continuous coupling between neurons. Existing neuromorphic implementations designed around spike-based interactions are not well-suited for emulating such models. Here view the distributed simulation of these models as message-passing algorithms on parallel hardware. Leveraging prior art in numerical algorithms and distributed simulation, we outline steps that enable the design of efficient digital neuromorphic accelerators for non-spiking neuronal models. In particular, we show that multi-bit packets, rather than spikes, are the most efficient communication strategy in packet-switched networks and that compared to basic numerical integration methods, higher-order differential equation solvers decrease both computation and communication costs while achieving lower numerical error, but that these benefits are ultimately limited by arithmetic precision. Using our proposed design principles, we convert an existing neuromorphic architecture into a distributed numerical solver - a spikeless neuromorphic system - for continuously-coupled neuronal models. We thereby demonstrate that our theoretical considerations indeed translate into practical advantages, namely reduced energy consumption and delay.
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All authors Jakob Jordan, Ole Richter, Congyang Li, Mihai A. Petrovici, Rajit Manohar

Hardware Architecture · Cross-listed from cs.LG

Beyond Flat Netlist: Hierarchical Graph Representation Learning for Scalable Analysis of Sequential Circuits

Circuit Representation Learning (CRL) offers a powerful paradigm to guide and optimize core Electronic Design Automation (EDA) tasks, but its practical adoption is hindered by the immense scale of industrial netlists and a failure to explicitly model register-level temporal dynamics. To overcome these barriers, we introduce DeepSeq3, a novel hierarchical framework that abstracts circuits into a two-level representation: fine-grained combinational subgraphs partitioned by flip-flops (FFs), and a high-level Super-Node Graph (SNG) that models the register-transfer structure. A dual Graph Neural Network (GNN) architecture learns representations at both levels, capturing local Boolean logic and global state transitions. Crucially, we introduce a state-centric pre-training scheme that predicts the reachability between FF states, endowing the model with a deep understanding of temporal behavior. Demonstrated on large-scale benchmarks, DeepSeq3's approach yields superior scalability and richer representations, reducing bounded model checking (BMC) solving time by 18% while guaranteeing correctness.
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All authors Jingyi Zhou, Zhengyuan Shi, Jiaying Zhu, Ziyang Zheng, Qiang Xu

Hardware Architecture

Gen-TAS: A Generative AI-Aided Hardware-Software Task Allocation Framework for FPGA-GPP Heterogeneous Systems

FPGA-GPP heterogeneous systems combine software flexibility with the performance and energy efficiency of reconfigurable hardware. However, determining which application tasks should execute on the GPP or FPGA requires extensive expertise and design-space exploration, particularly when user objectives vary across latency, communication, resource utilisation, and power. This paper proposes Gen-TAS, a knowledge-grounded LLM framework for user-specific FPGA-GPP task allocation. By combining task-graph analysis with RAG, Gen-TAS grounds LLM reasoning in historical implementation knowledge and generates multiple explainable strategies tailored to the specified objectives. Human-in-the-loop selection and a deterministic backend connect LLM-generated decisions to reproducible FPGA SoC implementations. Experiments on CNN and SDR workloads across multiple LLMs demonstrate stable, requirement-driven allocation. Under latency-oriented objectives, implementations following the selected strategies achieve speedups of up to 2.45$\times$ and 92.53$\times$, respectively, relative to the corresponding all-GPP baselines while other objectives select strategies that trade some acceleration performance for FPGA-GPP communication, resource utilisation, or FPGA power.
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All authors Mary Kong, Yuqin Zhao, Semih Vazgecen, Cristian Sestito, Themis Prodromakis

Hardware Architecture · Cross-listed from cs.DC

Great Expectations: Benchmarking the Real-World Performance of RVV 1.0 in HPC

Following the ratification of the RISC-V Vector Extension (RVV 1.0), new commercially available silicon has been adopting the extension. This paper revisits the question of RISC-V viability for High-Performance-Computing (HPC) by benchmarking the latest RVV 1.0-capable hardware (SiFive X280 (Tenstorrent Blackhole), SpacemiT X60 (K1) and X100/A100 (K3), and T-Head C920v2 (Sophon SG2044)). We assess these platforms using standard HPC benchmarks (BLAS, FFTW, HPL, HPCG) and synthetic workloads (STREAM, FMA throughput) and compare them to a state-of-the-art HPC ARM64 chip (NVIDIA Grace). Our findings show that while RVV 1.0 delivers significant performance improvements over scalar execution, hardware-specific implementation challenges remain. We detail these performance characteristics and discuss the remaining hurdles for RISC-V, including RVV, to become a mainstay in the HPC landscape.
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All authors Stepan Nassyr, Prateek Chawla, Daniel Seibel, Jayesh Badwaik, Kaveh Haghighi Mood, Andreas Herten

Hardware Architecture

AI Hardware Accelerators for Large Language Models: Architectures and the Memory Wall

Large language models (LLMs) place unprecedented and still-growing demands on the hardware that trains and serves them. This review surveys the full landscape of AI hardware accelerators for LLMs, including general-purpose GPUs, custom ASICs such as TPUs, Trainium, Groq, and Cerebras, reconfigurable FPGAs, processing-in-memory and near-memory architectures, and emerging neuromorphic and photonic approaches across cloud and edge deployment. Using the transformer's computational structure and roofline analysis as a common framework, we show that the decisive constraint on LLM acceleration is not arithmetic but memory: the autoregressive decode phase is bandwidth-bound, the key-value cache can rival the model weights in size, and data movement dominates energy. Comparing platforms on compute, memory, energy, programmability, and scalability, we find that no single architecture is optimal across workloads: GPUs remain the flexible default and the workhorse of training; domain-specific ASICs win at scale for stable, high-volume workloads; processing-in-memory is the most promising near-term response to the memory wall, entering systems as a heterogeneous complement; and neuromorphic and photonic computing, while promising, are not yet production-ready at frontier scale. Future progress depends on hardware-algorithm co-design and heterogeneous, memory-centric systems: for large language models, the memory system has become the computer.
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Thursday 27 August

Hardware Architecture · Cross-listed from cs.CV

Vision-centric generative AI models: A software-hardware perspective

Vision generative artificial intelligence (AI) has emerged as one of the most rapidly advancing areas of deep learning. The explosion of multimodal models has made them widely associated with text-to-image applications running on large datacentres. However, vision generative models are equally needed in applications that operate under strict hardware constraints at the edge, including autonomous vehicles, agricultural sensors, and mobile devices. In this Perspective, we argue that progress in vision generative AI has been driven by output quality, with hardware evolving reactively to accommodate growing model demands. We quantify the parameter cost and energy efficiency of these models across a range of accelerator platforms, and map four generative model families against seven real-world application domains. Finally, we advocate a software-hardware co-design approach, where deployment constraints are considered from the start of the design process, ensuring that the "right model" runs on the "right hardware" to serve the "right application", making generative AI deployment sustainable and accessible across a much broader range of platforms.
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All authors Eleni Tselepi, Cristian Sestito, Shady Agwa, Themis Prodromakis

Hardware Architecture

LLMs in Digital EDA: A perspective on shifting roles from Generation to Orchestration

Electronic design automation (EDA) has advanced engineering productivity through successive generations of tooling that progressively automate synthesis, optimisation, and verification. Large language models (LLMs) extend this trajectory by enabling direct translation from design intent to hardware implementations. In most of the EDA literature, LLM-based solutions are typically assisting siloed design stages or tasks, however this obscured the drivers by which capability emerges and systems scale. In this Perspective, we instead define three hierarchical roles that reveal how capability accumulates: a Generator that produces design artifacts in a single pass, an Agent that refines outputs through iterative tool feedback, and an Orchestrator that coordinates decisions across EDA-stages. Across published systems, this reveals a syntax trap in which models are trained to produce plausible code rather than physically correct hardware, compounded by fragmented tools and loss of design context that obscure how decisions affect later stages. Comparisons across the three roles show that current approaches struggle to scale to industrial designs, motivating a shift towards a standardised, physics-aware orchestrator that connects tools and agents across the EDA flow for more reliable and accessible hardware design.
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Hardware Architecture

HOLMES: In-Context Failure-Center Localization for High-Dimensional Yield Estimation

Importance sampling for high-sigma yield estimation requires locating the failure center from a severely imbalanced sample set. Existing surrogate-assisted methods rely on iterative gradient-based training, ill-posed under extreme class imbalance; model errors propagate into the estimator, causing accuracy collapse in high dimensions. We recast failure-center localization as few-shot binary classification: a prior-fitted tabular foundation model performs gradient-free in-context inference in a single forward pass, eliminating the ill-posed training loop. HOLMES (High-sigma Optimal Localization via Manifold Estimation and Sampling) pairs this with an SVD-based anisotropic proposal that captures the local geometry of the failure manifold, and a hit-rate-driven adaptive mixing scheme that stabilizes importance weights where conventional adaptation collapses. On 6T SRAM benchmarks spanning $D = 108$ to $D = 1{,}152$, full-dimensional baselines exhibit accuracy collapse at some dimension, with the strongest baseline reaching 25.8% relative error; PCA+MNIS is additionally evaluated at the two largest dimensions. HOLMES remains within 5.9% across all five configurations with up to $58.8\times$ speedup over Monte Carlo. The code is available on \href{https://github.com/IceLab-JCIE/ICE006-Yield-Holmes}
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All authors Wei W. Xing, Xixi Zhou, Kaiqi Huang, Jiaye Pan, Hong Qiu, Xin Wang, Shan Shen

Wednesday 26 August

Hardware Architecture

Redwood: A Frontier AI Accelerator Designed, Verified, and Deployed from Scratch in 2 Weeks by AI

Modern AI workloads and the hardware that runs them evolve on different timescales: architectural definition precedes volume silicon by years, while target workloads shift in months. Design decisions are therefore committed under deep uncertainty and paid for twice, once in the generality added as a hedge, and again when new workloads map poorly onto frozen silicon. As Moore's Law stagnates, specialization is the main remaining source of performance-per-watt and demands a design cycle that runs at the cadence of the workloads. We present an end-to-end AI system that collapses the software-to-silicon stack into a single optimization loop, where hardware and software are co-designed and verified under one objective. Its first demonstration is Redwood, a frontier AI accelerator built for single-batch, low-power, ultra-low-latency inference for physical AI. From a high-level specification by two human architects, the system autonomously generated the performance model, RTL design, UVM environments, formal proofs, firmware, and kernels in under two weeks with no human intervention below the specification. Every block reached 95% coverage via commercial EDA tools, our proprietary formal engine, and hardware-in-the-loop validation. Specification changes were reverified and redeployed to hardware in under 48 hours. Redwood Nano, its ultra-low-power FPGA variant, runs multi-billion-parameter models like Llama and Qwen. Projected onto Samsung 8 nm, the Jetson Orin Nano's process class, Redwood delivers 1.75x the throughput at 1.9x lower power, a 3.4x performance-per-watt gain against a measured Jetson baseline on the same models. Qwen running on Redwood also helped design next-generation Redwood, an early step toward recursive self-improvement. To our knowledge, this is the first production-worthy AI accelerator designed end-to-end by an AI system and running a modern AI model.
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Hardware Architecture · Cross-listed from cs.CR

SILK: Closing the Time-of-Check-to-Time-of-Use Gap in RoT-Protected AI Systems

Root-of-trust (RoT) authentication verifies a DNN model at load time, but weights may subsequently traverse DRAM, DMA, interconnect, and prefetch paths before reaching the compute engine. Post-verification tampering along this path can therefore alter the weights actually consumed while leaving the authenticated model image unchanged, creating a time-of-check-to-time-of-use (TOCTOU) integrity gap. We present SILK (Streaming Inline Lightweight Keying), an in-place integrity mechanism that verifies the weight stream at the final pre-compute boundary. SILK repurposes quantized-weight LSBs as secret-keyed integrity bits and chains dependencies across weight bytes, so a local modification perturbs multiple integrity checks. A lightweight streaming checker recomputes these checks without separate authentication tags and uses commit gating to prevent unverified weights from reaching computation. Under a secure pseudorandom function (PRF), the forgery probability decreases exponentially with the number of affected checks, and measured miss rates closely track the analytical bound. SILK detects every stream-modifying instance in our functional attack suite. For INT8, it limits quality loss to at most 0.76 pp across evaluated CNNs and 0.17 perplexity across eight LLMs, while INT4 and MXFP4 provide a configurable security-quality tradeoff through check sparsity. On a Xilinx ZCU102, the synthesized reference pipelined implementation sustains 756 MB/s at only 1.00% of the equivalent area cost of a Caliptra 2.x RoT, while a configuration with a conservative per-attempt forgery bound of 2^-128 still sustains 678 MB/s at 6.15% of the RoT cost.
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All authors Ruichen Qi, Xinting Jiang, Ema Dimitrova, Junyi Luo, Quan Cheng, Mehdi Saligane

Hardware Architecture · Cross-listed from cs.ET

An Economic Analysis of DNA-based Data Storage Systems

Deoxyribonucleic acid (DNA) remains stable for millennia without degradation, can store information at densities orders of magnitude higher than current technologies, and is environmentally friendly due to its low energy requirement. While these advantages make it a promising candidate for storing archival data, DNA storage systems are constrained by high costs, particularly those associated with DNA synthesis. In this paper, we present a comprehensive cost model for calculating the cost of archiving data using various storage systems. Leveraging our model, we conduct a cost analysis of DNA storage versus leading magnetic tape and cloud-based archival storage services. Furthermore, this model can be customised with various parameters to reflect future cost declines and other cost-relevant trends. Our results indicate that, under current cost trajectories, DNA storage costs must fall by eight to nine orders of magnitude to become economically competitive with today's data archival technologies. Moreover, we explore multiple "what-if" scenarios over the coming decades, quantifying the rate of cost decline required to close the competitiveness gap relative to tape and cloud archives. Our findings underscore the critical need for accelerated innovation and investment in DNA synthesis technologies to reduce their cost and transform DNA storage into a practical archival solution.
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Hardware Architecture

Beyond Edge Cuts: Activity-Weighted Multicast Hypergraph Mapping for Spiking Neural Networks on Mesh NoCs

Mapping spiking neural networks (SNNs) onto neuromorphic many-core platforms is often formulated with graph partitioning and pairwise placement costs. That abstraction is convenient, but it does not match the physical communication event: one spike from a source neuron is delivered to a set of postsynaptic destinations, and routes to several destinations can share mesh links. We present M-HySMap, a route-aware, activity-weighted multicast hypergraph mapping framework. Each source neuron induces a directed hyperedge to its postsynaptic fanout, weighted by profiled activity. The mapper starts from strong activity-aware graph/QAP seeds and then optimizes distinct destination-core fanout, the union of deterministic mesh routes, and link congestion. The central algorithmic observation is locality: moving one neuron can change only its own source-rooted hyperedge and the hyperedges of its predecessors. This permits exact incremental gain evaluation while caching every unaffected route contribution. We expose this combinatorial structure in detail, derive a conservative placement lower bound, and describe a portfolio of partition and placement neighborhoods that preserves the best incumbent. Across a 115-job evidence suite on Potjans-inspired recurrent SNNs and mesh NoCs from 4 x 4 to 6 x 6, plus a 7 x 7 stress case, M-HySMap reduces routed multicast hops by 10.6-19.6% over Activity+QAP and 19.7-41.1% over Edge+QAP. Incremental updates accelerate refinement by 4.7-12.7x while matching full recomputation to numerical precision.
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Hardware Architecture

MeshReduce-U: Compiler-Guided Communication Reduction for Irregular Neural Reductions on Mesh NoCs

Many irregular neural workloads induce skewed many-to-one reductions with repeated neighborhoods and nonlocal communication. Conventional NoC mappers optimize placement and routes for a fixed communication graph, even though associative reductions expose legal opportunities to eliminate traffic before routing. We present MeshReduce-U, a compiler-guided communication-reduction and routing framework for mesh-NoC-based spatial accelerators. MeshReduce-U coalesces colocated sources, forms local aggregation islands, blocks channels with compatible fan-in structure, selects capacity-feasible sinks, and routes the remaining fixed-width carriers using fused usage-aware costs. A deterministic route-replay model reports schedule-derived communication latency, total link usage (TLU), and fused link usage (FusedTLU) separately. Across a 20-workload lowerable neural-network zoo, MeshReduce-U reduces mean latency, TLU, and FusedTLU by 40.3%, 56.0%, and 48.7%, respectively, relative to an ABC-style source-aggregation baseline, improving all three metrics on every workload. Across 40 synthetic irregular reductions, it reduces mean latency and TLU by 12.3% and 19.7%. A new 30-instance pass-by-pass study further shows that the structural rewrites reduce the global carrier count by 60.9% and replay latency by 63.0%. These results show that rewriting reducible neural communication before routing can be more effective than searching harder over an unreduced traffic graph.
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Hardware Architecture

Ankhdjet: An Open-Source Compiler for Mask-Programmed Ternary Compute-in-ROM on an Open PDK

Large-language-model inference is dominated by weight movement: every generated token re-reads every weight. Ternary quantization (BitNet b1.58) shrinks each weight to 1.58 bits with reported parity at the 2B-parameter scale, small enough that hardwiring the weights into a read-only mask becomes plausible, and a commercial chip (Taalas HC1) has validated hardwired weights on an advanced node behind closed tooling. This paper asks whether model-specific silicon can be made reproducible with entirely open infrastructure. We present Ankhdjet, an open-source compiler that lowers a HuggingFace ternary checkpoint (BitNet b1.58 and its kin) to a via-mask program of a fixed compute-in-ROM macro on the open SKY130 PDK, verified end to end with open tools. We defend two claims: (1) the first open-source weights-to-mask compute-in-ROM compiler on a fabricable open PDK, taken through full open-toolchain signoff (KLayout DRC zero, netgen LVS zero, clean timing) twice with two different weight matrices through an identical flow in which only the mask differs; and (2) the first compute-in-ROM macro submitted for fabrication on an open PDK (TinyTapeout/ChipFoundry SKY130 shuttle ttsky26c, silicon expected 2027). The compiler's read is fully digital (full-swing bitline sampling into standard cells, so the emission ports to any node by synthesis); an analog comparator readout of the same machine is retained as a measured variant, replaced by the digital readout at one eighth the area. We additionally report the per-level adversarial verification methodology that caught three DRC-invisible silent shorts, a negative result on storing two ternary weights per transistor at 130 nm, and which analog sense techniques survive at which nodes. Read energy is from extracted-parasitic simulation (0.98-1.73 pJ per sensed weight); no energy measurements are claimed, and the fabricated vehicles are demonstrators.
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Hardware Architecture

Integrated Hardware Annealing based on Langevin Dynamics for Ising Machines

Ising machines are non-von Neumann machines designed to solve combinatorial optimization problems (COP) by searching for the ground state, or the lowest energy configuration, within the Ising model. However, Ising machines often face the challenges of getting trapped in local minima due to the complex energy landscapes. Hardware annealing algorithms help mitigate this issue by using a probabilistic approach to steer the system toward the ground state. In this paper, we present a hardware annealing algorithm for Ising machines based on Langevin dynamics, a stochastic perturbation by random noise. Theoretical analysis, system-level design, and detailed circuit design are carried out. We evaluate the performance of the algorithm through chip-level simulation using a standard 65-nm CMOS technology to demonstrate the algorithm's efficacy. The results show that the proposed hardware annealing algorithm effectively guides the system to reach the ground state with a probability of 86.5%, significantly improving the solution quality by 97.5%. Further, we compare the algorithm with state-of-the-art hardware annealing methods through behavioral-level simulations, highlighting its improved solution quality alongside a 50% reduction in time-to-solution.
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All authors Yongchao Liu, Lianlong Sun, Michael Huang, Hui Wu

Hardware Architecture · Cross-listed from cs.CR

From Fleet to Lab: Revisiting the Security and Complexity of Industrial Rowhammer Mitigation

This paper studies efficient and secure Rowhammer mitigation at the Memory-Controller (MC). Rowhammer mitigation faces a fundamental tradeoff between tracking storage and mitigation rate: precise trackers (such as Misra-Gries) avoid unnecessary mitigations but require large CAM structures, whereas sampling-based schemes (such as PARA) require no storage but incur frequent mitigations even when not under attack. Microsoft recently deployed Sigries, an MC-side Rowhammer defense that combines an under-provisioned Misra-Gries tracker with a row-sampling fallback, in its Azure Cobalt 200 SoC. Sigries observed that the tracker-to-sampling transition can be insecure, and claimed the reverse transition is always safe. Our analysis shows that this transition is also vulnerable, and a Round-Robin Attack across sub-banks reduces the MTTF of Sigries to about 1 second, 8 orders of magnitude below the 13 years with PARA. Sigries also suffers from CAM complexity and high storage overheads. Our proposal, FiRM (Filtered Rowhammer Mitigation), is based on the insight that, for a secure design, the tracking-mode and sampling-mode should not be configured independently but co-designed to ensure the system remains secure not only in both modes but also during transitions. FiRM incurs zero slowdown for benign workloads, since they do not exceed the filtering threshold, and also replaces the complex CAM-based tracker with simple SRAM filters. To handle stressful patterns, we propose FiRM-P (probabilistic) and FiRM-D (deterministic). FiRM-P uses varying probabilities during transitions and steady state to ensure both security and low performance overhead. FiRM-D provides guaranteed deterministic security by modulating the rate of mitigation. Both FiRM-P and FiRM-D have less storage overhead than Sigries. Our paper shows that a principled approach can avoid both the insecurity and the complexity of Sigries.
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Hardware Architecture · Cross-listed from cs.CR

RTLGuard: A Lightweight Teacher-Student Defense for Poisoned RTL Code Generation Models

The rapid advancement of large language models (LLMs) is driving a shift toward automated register transfer level (RTL) code generation, enabling designers to translate high-level specs. into synthesizable hardware. However, this reliance on pre-trained (3rd-party) fine-tuned models may introduce critical trust issues, as the training data and adaptation process of these models are often opaque. Thus, adversaries (even model providers) may embed hidden backdoor threats during fine-tuning, allowing malicious behavior, e.g., hardware Trojans, to be triggered by seemingly benign prompts given by victim user at inference time. In this paper, we introduce RTLGuard, to mitigate such a trust issue in AI-enabled IC supply chain. Rather than prohibitive computational cost of full-parameter retraining, RTLGuard leverages a teacher-student framework designed to sanitize compromised RTL generation models by (1) fine-tuning a small-scale, "clean" teacher model on a limited set of trusted RTL data, (2) guiding the poisoned target model via a composite teacher-student objective, and (3) incorporating feature alignment and knowledge distillation to suppress malicious behaviors. Our experiments across various LLM architectures demonstrate that RTLGuard significantly reduces the Attack Success Rate (ASR) while preserving the functional correctness and synthesizability of the generated RTL code.
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Hardware Architecture

Syn2Logic: End-to-End Neuromorphic Design Automation

In this work, we propose a view on electronic Neuromorphic Design Automation (eNDA), which we see as a design automation flow that bridges computational neuroscience modeling with traditional Electronic Design Automation (EDA) flow. We introduce the term, give examples of how it can be implemented, and design a prototype implementation: Syn2Logic. Syn2Logic is an entire eNDA framework, that allows neuroscientists to model neural behavior using a custom DSL and a compiler that takes the same model description down to synthesizable RTL hardware. We end the paper by applying the eNDA-flow through Syn2Logic to show how to – without writing a single line of hardware description language (HDL) code– (i) generate what we believe is the fastest C. elegans accelerator that runs significantly faster than state-of-the-art simulators, (ii) create (to the best of our knowledge) the fastest, most generic neuromorphic sudoku solver that outperforms CP-SAT and SCIP on TOP1465 puzzles, (iii) create a 5.6 million FPS/Watt accelerator on a tiny FPGA that outperforms existing neuromorphic architectures in terms of speed and energy-efficiency on the MNIST dataset, and (iv) create a generic accelerator for unsupervised learning that outperforms most existing unsupervised methods on the OPS-SAT benchmark.
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Hardware Architecture

APT: Accelerating Diffusion Transformers via Attention Probability-Guided Pruning and Quantization

Recent advances in generative AI have significantly increased the demand for high-resolution image and video generation, positioning diffusion models as a core technology. Among them, Diffusion Transformers (DiTs) have emerged as the state-of-the-art (SOTA) models due to their scalability and output quality. However, self-attention in DiTs incurs significant computational overhead, leading to excessively long latency as the complexity grows with the fourth power of the output resolution. While prior works have attempted to mitigate this cost using sparsity and quantization techniques, they fall short of effectively reducing the computational cost in high-resolution DiTs. In this paper, we present APT, a software-hardware co-designed accelerator for high-resolution DiTs. APT leverages attention probabilities as a unified importance metric to jointly optimize computation through fine-grained pruning and adaptive precision scaling. At the algorithm level, we propose Attention Probability-guided Adaptive Dual Thresholding (APDT), which dynamically performs element selection and precision assignment using dual thresholds. To ensure compatibility with memory-efficient FlashAttention, we introduce Timestep-Aware FlashAttention (TAFA), which predicts attention probabilities across timesteps by exploiting temporal similarity. At the architecture level, we co-design a specialized accelerator that efficiently supports irregular sparsity and dual-precision execution, featuring dynamic mask management, address translation, dual-precision compute units, and a tile-based dataflow. Finally, we evaluate APT on SOTA DiT models, including PixArt-$\alpha$, Stable Diffusion 3, and FLUX. APT achieves up to 8.16$\times$ speedup and 14.98$\times$ higher energy efficiency over NVIDIA A100, and up to 3.01$\times$ speedup and 2.04$\times$ higher energy efficiency over EXION, a SOTA diffusion model accelerator.
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All authors Sungyeob Yoo, Seeyeon Kim, Joonyong Park, Seunghee Han, Joo-Young Kim

Hardware Architecture

BOOSTEDSOSA: Accelerated Inferencing for Low Variance Stochastic Online Scheduling

Heterogeneous scheduling in stochastic, online envi- ronments, such as high-performance computing (HPC) systems, presents a significant challenge. Stochastic Online Scheduling Accelerators (SOSAs) offer a promising solution, but their effectiveness is compromised by a reliance on runtime estimates provided by users. These estimates introduce substantial vari- ance into the scheduling process (mean MAE in hundreds of Core-Days), thereby weakening the competitiveness of Stochastic Online Scheduling algorithms as their competitive-ratio bound increases with runtime variability. To address this limitation, we introduce BOOSTEDSOSA, a dual-FPGA ML-assisted Scheduling architecture that integrates a Machine Learning predictor for expected processing times, with a novel temporal-aware training policy. The predictor estimates job runtimes using only scheduler parameters available at submission time, enabling its use in existing HPC systems. Using historical real-world HPC job data (from the Argonne Leadership Comput- ing Facility, MIT Supercloud and UIUC Blue Waters workload datasets), we show that the predictor reduces MAE by up to 63.85% compared to user runtime estimates, and the additive training policy reduces MAE by up to 71.88% compared to a static model. End-to-end, BOOSTEDSOSA achieves an average 17x speedup over an AVX-optimized software baseline and processes up to 1,711 jobs/seconds
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All authors Adam H. Ross, Riccardo Revalor, Aryan Singh, Ayush Jain, Debjit Pal

Tuesday 25 August

Hardware Architecture · Cross-listed from cs.CR

Automotive HSMs - Architectural Challenges and Security Implications

Automotive electronic control units (ECUs) increasingly depend on hardware-rooted security to protect software integrity, authenticity, and lifecycle management in the presence of remote and physical threats. Hardware Security Modules (HSMs) have become a key building block in automotive system-on-chips (SoCs), providing isolated cryptographic services, secure key storage, and controlled execution under stringent real-time and cost constraints. This paper presents an architectural analysis of automotive HSMs and examines their role in establishing secure boot and hardware roots of trust. We first survey common HSM integration models used in production ECUs and discuss their flexibility and current automotive use cases. We then introduce realistic threat models to motivate hardware-backed security controls and analyze how HSM design choices influence secure boot chains of trust, secure storage, secure execution, and software signing mechanisms. Key tradeoffs between isolation, performance, updateability, and attack surface are discussed, with optional consideration of side-channel implications. The paper concludes by highlighting open challenges and future directions for scalable and resilient automotive hardware security. Finally, we discuss emerging challenges such as cryptographic agility and post-quantum readiness that are likely to shape the next generation of automotive HSM architectures.
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Hardware Architecture

An Open-Source Benchmark Suite of 3D-IC Testcases

The physical design community has benefited from standardized, publicly available benchmark suites, which have enabled reproducible evaluation and driven significant advances in 2D place-and-route algorithms over the past three decades. However, the emergence of 3D heterogeneous integration technologies, including through-silicon vias (TSVs), hybrid bonding, and chiplet-based architectures, has introduced new physical design challenges that are not captured by existing planar benchmarks. Although several 3D-IC design examples have been reported, publicly accessible and scalable benchmark suites that enable reproducible evaluation across different 3D physical design problems remain limited. In this paper, we present an open-source suite of 3D-IC benchmark testcases derived from representative chiplet-based case studies in CATCH, an open-source framework for estimating the cost of heterogeneous integration architectures. The proposed benchmark suite provides reusable virtual chiplet models covering compute, memory, I/O, analog, and substrate components. Each testcase captures essential physical design characteristics of 3D systems, including heterogeneous die integration, inter-die connectivity, and technology-dependent design constraints. By publicly releasing these benchmarks, we aim to establish a common evaluation platform and accelerate community-wide research progress in 3D heterogeneous integration.
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All authors Rohan Soni, Jooyeon Jeong, Alexander Graening, Anthony Foo, Richard Chen, Puneet Gupta

Hardware Architecture

FLINT: Efficiently Leveraging High Bandwidth Flash for Capacity-Scalable LLM Inference Acceleration

LLM inference is increasingly constrained by accelerator memory capacity rather than compute throughput. This constraint is especially acute in single-accelerator and small-node inference systems, where limited on-package memory capacity restricts the size of deployable models. HBF is an emerging 3D-stacked NAND flash technology that provides multi-terabyte near-accelerator capacity, making it a promising capacity tier for storing LLM weights. However, existing HBF-based proposals face three adoption challenges: they (1) rely on coarse-grained static prefetching for LLM weights aiming to hide the microsecond-level read latency of the NAND flash device while maximizing HBF's read throughput, (2) expose NAND flash management tasks (e.g., refresh operations) to the accelerator-visible critical inference path, and (3) miss optimization opportunities to specialize and optimize the flash-management mechanisms to the workload behavior. Our goal is to design an efficient HBF substrate that integrates HBF as a memory-capacity tier alongside HBM while addressing these three challenges. To this end, we propose FLINT, a workload-driven HBF substrate for capacity-scalable LLM inference. FLINT introduces three mechanisms: (1) a hardware burst-buffer controller that dynamically coalesces and pipelines HBF reads aiming to utilize existing NAND flash buffers while sustaining high HBF bandwidth, (2) a phantom-plane refresh mechanism, which removes refresh from the critical inference path by moving refresh-related NAND flash operations outside the read foreground back via low-cost resource duplication, and (3) a read-only FTL, which replaces SSD-class support for arbitrary writes with a compact table that translates logical weight bursts to physical HBF locations.
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All authors Geraldo F. Oliveira, Arash Tavakkol, Xiangyu Zhu, Ahmet Caner Yüzügüler, Vamanan Arulchelvan, Lukas Cavigelli, Renzo Andri, Mohammad Sadrosadati, Jia Xinglei, Onur Mutlu, Zhou Ke, Shai Bergman, Ji Zhang

Hardware Architecture

Hydra: Phase-Aware Workload Characterization of LLM Inference across Edge SoC Generations, Backends, and Quantization Levels

Edge LLM deployment is shaped by more than model size and precision: inference backend, hardware platform, memory traffic, and power management all affect latency and efficiency. We present Hydra, a common-schema, phase-aware workload characterization framework for LLM inference on edge SoCs. Hydra instruments HuggingFace Transformers and llama.cpp with a shared per-prompt timing schema and fuses those records with hardware telemetry, enabling a multi-dimensional characterization of performance, system-resource utilization, and efficiency across prefill and decode phases. Using Hydra, we evaluate three consecutive edge System-on-Chip (SoC) generations (AGX Xavier, AGX Orin, and AGX Thor), 13 instruction-tuned LLMs from seven families, five execution formats, and consider input/output-length sensitivity. The resulting artifact contains roughly 107K per-prompt records and is publicly released with Hydra. Our analysis shows that aggregate latency alone hides key deployment effects: backend structure changes where latency is introduced, quantization reduces memory traffic and energy but does not predict power monotonically, and SoC generation changes how utilization and efficiency should be interpreted. By connecting phase-level timing with system-resource utilization and efficiency metrics, Hydra enables reproducible, phase-aware characterization of edge LLM inference. Hydra's source code and the collected per-prompt trace corpus are available open-source at: https://github.com/amirtaherin/hydra
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All authors Amir Taherin, Sana Taghipour Anvari, Charles Amante, Yixiao Chen, Ruben Noroian, Zlatan Feric, Nicolas Bohm Agostini, Pu Zhao, José Cano, Bin Ren, Yanzhi Wang, David Kaeli

Hardware Architecture

Maia 200: A Software Defined Dataflow System for Large-scale AI Acceleration

We introduce Maia 200, an advanced AI accelerator delivering high performance-10 145 Tflop/s FP4 and 5072 Tflop/s FP8 within a 750W TDP and 7 TB/s HBM bandwidth. Maia exemplifies a new class of Software Defined Locally Accessed Dataflow Architectures (SDLA), which explicitly program dataflow engines to orchestrate highly specialized memories and data movement engines. This approach shifts the focus from today's thread-centric to data-movement-centric architecture, improving efficiency and scalability. Our taxonomy of data management, inspired by Flynn's classification, highlights how SDLA addresses challenges in modern AI computing. Maia 200 achieves significant cost and energy savings while supporting massive parallelism for AI inference workloads, making it a compelling solution for next-generation high-performance computing systems.
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All authors Sherry Xu, Marco Heddes, Jackson Peng, Tom Savell, Monica Tang, Prashant Ranjan, Jesse Benson, Ofer Dekel, Saurabh Dighe, Anupama Kurpad, Artour Levin, Matthew Mattina, George Petre, Cheng Tang, Yuan Yu, Li Zhang, Torsten Hoefler

Hardware Architecture

Simthesizer: An Agent-Driven Simulation Framework for LLM Serving Systems

System-level simulation is an essential tool for exploring the rapidly expanding design space of LLM serving systems, where real deployments remain costly and often infeasible. However, modern LLM serving now evolves faster than human-driven simulator development can track, and emerging workloads and mechanisms, from agentic workflows to disaggregated serving, no longer fit the monolithic simulation pipeline that existing simulators assume. Each new mechanism therefore demands an invasive rewrite, leaving a widening development gap between deployed serving systems and the simulators that model them. To close this gap, we present Simthesizer, a framework that realizes agent-driven simulator development. Simthesizer introduces a composable simulator infrastructure that uniformly expresses the complete serving workflow, including the control decisions that coordinate it, and realizes it as a unified dynamic graph in Simthesizer simulator. Synthesizer agent, a harnessed coding agent, then lowers natural-language feature requests onto this abstraction under simulator-specific guardrails and fidelity validation, evolving one shared simulator instead of building a new one for every feature. Under the same coding agent and harnesses, extensions built on Simthesizer follow a vLLM-based real system with 2.51% average throughput error, versus 6.03% for extensions built on existing simulators. On identical workloads, Simthesizer also simulates up to 284.96x and 23.19x faster than two state-of-the-art simulators, LLMServingSim2.0 and Vidur, respectively.
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All authors Wonung Kim, Hyunmin Choi, Minsu Kim, Jaehong Cho, Yeongwook Kim, Jongse Park

Hardware Architecture

Cross-Layer Analysis of Thermal Tuning Stalls in Wafer-Scale Optical Interconnects for LLM MoE Training

Mixture-of-experts (MoE) training depends heavily on all-to-all communication, which wafer-scale optical interconnects with dense wavelength-division multiplexing can serve. Their microring resonators rely on thermo-optic tuning, while MoE compute bursts swing the photonic-layer temperature by about 10 K within tens of milliseconds. This paper quantifies the communication stall by coupling packet-level network simulation, transient thermal simulation of a 3D-stacked GPU and photonic die, and a ring detuning criterion, and by feeding the stall back into the network timeline until both agree. Including this feedback, a tracking loop at the measured 5 nm/s lengthens the training iteration of Mixtral 8x7B and LLaMA-MoE 6.7B by factors of about 1.16 and 1.25 at full model depth. Measured H100 die temperatures match the modeled swing of 300 ms bursts within 15%. A loop slewing eight times faster, a heater driven at each kernel launch, or a dummy load near 75% of peak power removes the stall. An athermalized lithium-niobate ring with a non-volatile ferroelectric setpoint removes it with no holding power or fast loop, which makes it suitable for wafer-scale optical interconnects.
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