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Deep neural network (DNN) models are increasingly deployed in real-time, safety-critical systems such as autonomous vehicles, driving the need for specialized AI accelerators. However, most existing accelerators support only non-preemptive execution or limited preemptive scheduling at the coarse granularity of DNN layers. This restriction leads to frequent priority inversion due to the scarcity of preemption points, resulting in unpredictable execution behavior and, ultimately, system failure. To address these limitations and improve the real-time performance of AI accelerators, we propose DERCA, a novel accelerator architecture that supports fine-grained, intra-layer flexible preemptive scheduling with cycle-level determinism. DERCA incorporates an on-chip Earliest Deadline First (EDF) scheduler to reduce both scheduling latency and variance, along with a customized dataflow design that enables intralayer preemption points (PPs) while minimizing the overhead associated with preemption. Leveraging the limited preemptive task model, we perform a comprehensive predictability analysis of DERCA, enabling formal schedulability analysis and optimized placement of preemption points within the constraints of limited preemptive scheduling. We implement DERCA on the AMD ACAP VCK190 reconfigurable platform. Experimental results show that DERCA outperforms state-of-the-art designs using non-preemptive and layer-wise preemptive dataflows, with less than 5 % overhead in worst-case execution time (WCET) and only 6% additional resource utilization. DERCA is open-sourced on GitHub: https://github.com/arc-research-lab/DERCA 

GPUs are critical for compute-intensive applications, yet emerging workloads such as recommender systems, graph analytics, and data analytics often exceed GPU memory capacity. Existing solutions allow GPUs to use CPU DRAM or SSDs as external memory, and the GPU-centric approach enables GPU threads to directly issue NVMe requests, further avoiding CPU intervention. However, current GPU-centric approaches adopt synchronous I/O, forcing threads to stall during long communication delays. We propose AGILE, a lightweight asynchronous GPU-centric I/O library that eliminates deadlock risks and integrates a flexible HBM-based software cache. AGILE overlaps computation and I/O, improving performance by up to 1.88 × across workloads with diverse computation-to-communication ratios. Compared to BaM on DLRM, AGILE achieves up to 1.75 × speedup through efficient design and overlapping; on graph applications, AGILE reduces software cache overhead by up to 3.12 × and NVMe I/O overhead by up to 2.85 × ; AGILE also lowers per-thread register usage by up to 1.32 ×. 

Real-time systems are widely applied in different areas like autonomous vehicles, where safety is the key metric. However, on the FPGA platform, most of the prior accelerator frameworks omit discussing the schedulability in such real-time safety-critical systems, leaving deadlines unmet, which can lead to catastrophic system failures. To address this, we propose the ART framework, a hardware-software co-design approach that transforms baseline accelerators into “real-time guaranteed" accelerators. On the software side, ART performs schedulability analysis and preemption point placement, optimizing task scheduling to meet deadlines and enhance throughput. On the hardware side, ART integrates the Global Earliest Deadline First (GEDF) scheduling algorithm, implements preemption, and conducts source code transformation to transform baseline HLS-based accelerators into designs targeted for real-time systems capable of saving and resuming tasks. ART also includes integration, debugging, and testing tools for full-system implementation. We demonstrate the methodology of ART on two kinds of popular accelerator models and evaluate on AMD Versal VCK190 platform, where ART meets schedulability requirements that baseline accelerators fail. ART is lightweight, utilizing <0.5% resources. With about 100 lines of user input, ART generates about 2.5k lines of accelerator code, making it a push-button solution. 

As AI continues to grow, modern applications are becoming more data- and compute-intensive, driving the development of specialized AI chips to meet these demands. One example is AMD's AI Engine (AIE), a dedicated hardware system that includes a 2D array of high-frequency very-long instruction words (VLIW) vector processors to provide high computational throughput and reconfigurability. However, AIE's specialized architecture presents tremendous challenges in programming and compiler optimization. Existing AIE programming frameworks lack a clean abstraction to represent multi-level parallelism in AIE; programmers have to figure out the parallelism within a kernel, manually do the partition, and assign sub-tasks to different AIE cores to exploit parallelism. These significantly lower the programming productivity. Furthermore, some AIE architectures include FPGAs to provide extra flexibility, but there is no unified intermediate representation (IR) that captures these architectural differences. As a result, existing compilers can only optimize the AIE portions of the code, overlooking potential FPGA bottlenecks and leading to suboptimal performance. To address these limitations, we introduce ARIES, an agile multi-level intermediate representation (MLIR) based compilation flow for reconfigurable devices with AIEs. ARIES introduces a novel programming model that allows users to map kernels to separate AIE cores, exploiting task- and tile-level parallelism without restructuring code. It also includes a declarative scheduling interface to explore instruction-level parallelism within each core. At the IR level, we propose a unified MLIR-based representation for AIE architectures, both with or without FPGA, facilitating holistic optimization and better portability across AIE device families. For the General Matrix Multiply (GEMM) benchmark, ARIES achieves 4.92 TFLOPS, 15.86 TOPS, and 45.94 TOPS throughput under FP32, INT16, and, INT8 data types on Versal VCK190 respectively. Compared with the state-of-the-art (SOTA) work CHARM for AIE, ARIES improves the throughput by 1.17x, 1.59x, and 1.47x correspondingly. For ResNet residual layer, ARIES achieves up to 22.58x speedup compared with optimized SOTA work Riallto on Ryzen-AI NPU. ARIES is open-sourced on GitHub: https://github.com/arc-research-lab/Aries. 

FPGA-based edge servers are used in many applications in smart cities, hospitals, retail, etc. Equipped with heterogeneous FPGA-based accelerator cards, the servers can be implemented with multiple tasks including efficient video prepossessing, machine learning algorithm acceleration, etc. These servers are required to implement inference during the daytime while re-training the model during the night to adapt to new environments, domains, or new users. During the re-training, conventionally, the incoming data are transmitted to the cloud, and then the updated machine learning models will be transferred back to the edge server. Such a process is inefficient and cannot protect users’ privacy, so it is desirable for the models to be directly trained on the edge servers. Deploying convolutional neural network (CNN) training on heterogeneous resource-constrained FPGAs is challenging since it needs to consider both the complex data dependency of the training process and the communication bottleneck among different FPGAs. Previous multi-accelerator training algorithms select optimal scheduling strategies for data parallelism, tensor parallelism, and pipeline parallelism. However, pipeline parallelism cannot deal with batch normalization (BN) which is an essential CNN operator, while purely applying data parallelism and tensor parallelism suffers from resource under-utilization and intensive communication costs. In this work, we propose MTrain, a novel multi-accelerator training scheduling strategy that transfers the training process into a multi-branch workflow, thus independent sub-operations of different branches are executed on different training accelerators in parallelism for better utilization and reduced communication overhead. Experimental results show that we can achieve efficient CNN training on heterogeneous FPGA-based edge servers with 1.07x-2.21x speedup under 15 GB/s peer-to-peer bandwidth compared to the state-of-the-art work. 

In recent years, security monitoring of public places and critical infrastructure has heavily relied on the widespread use of cameras, raising concerns about personal privacy violations. To balance the need for effective security monitoring with the protection of personal privacy, we explore the potential of optical fiber sensors for this application. This article proposes FiberFlex, an intelligent and distributed fiber sensor system. Ultizing Field Programmable Gate Arrays (FPGA) high-level synthesis (HLS) acceleration, FiberFlex offers real-time pedestrian detection by co-designing the entire pipeline of optical signal acquisition, processing, and recognition networks based on the principles of optical fiber sensing. As a promising alternative to traditional camera-based monitoring systems, FiberFlex achieves pedestrian detection by analyzing the vibration patterns caused by pedestrian footsteps, enabling security monitoring while preserving individual privacy. FiberFlex comprises three modules:First, fiber-optic sensing system: A fiber-optic distributed acoustic sensing (DAS) system is built and used to measure the ground vibration waves generated by people walking.Second, algorithms: We first collect the training data by measuring the ground vibration waves, label the data, and use the data to train the neural network models to perform pedestrian recognition.Third, hardware accelerators: We use HLS tools to design hardware modules on FPGA for data collection and pre-processing and integrate them with the downstream neural network accelerators to perform in-line real-time pedestrian detection. The final detection results are sent back from FPGA to the host CPU. We implement our system FiberFlex with the in-house built DAS system and AMD/Xilinx Kintex7 FPGA KC705 board and verify the whole system using the real-world collected data. We conduct recognition tests on five test subjects of varying ages, heights, and weights in a fixed sensing area. Each subject experienced 20 real-time recognition tests using their daily walking habits, and the subjects were given adequate rest between tests. After 100 tests on five test subjects, the overall real-time recognition accuracy exceeded\(88.0\%\). The whole system uses 55 W of power, 33 W in the optical DAS system and 22 W in the FPGA. Relying on its end-to-end interdisciplinary design, FiberFlex seamlessly combines fiber-optic sensors with FPGA accelerators to enable low-power real-time security monitoring without compromising privacy, making it a valuable addition to the existing security monitoring network. According to FiberFlex, more valuable research can be conducted in the future, such as fall monitoring for the elderly, migration of identification networks between different application scenarios, and improvement of anti-interference performance in more complex environments. In future perception networks, where the “eyes” are not feasible, let’s use fiber optic touch instead. 

Data centers have been relying on renewable energy integration coupled with energy efficient specialized processing units and accelerators to increase sustainability. Unfortunately, the carbon generated from manufacturing these systems is be- coming increasingly relevant due to these energy decarbonization and efficiency improvements. Furthermore, it is less clear how to mitigate this aspect of embodied carbon. As workloads continue to evolve over each hardware generation we explore the tradeoffs of fabricating new application-tuned hardware compared with more general solutions such as Field Programmable Gate Arrays (FPGAs). We also explore how REFRESH FPGAs can amortize embodied carbon investments from previous generations to meet the requirements of future generations workloads. 

While Vision Transformers (ViTs) have shown consistent progress in computer vision, deploying them for real-time decision-making scenarios (< 1 ms) is challenging. Current computing platforms like CPUs, GPUs, or FPGA-based solutions struggle to meet this deterministic low-latency real-time requirement, even with quantized ViT models. Some approaches use pruning or sparsity to reduce model size and latency, but this often results in accuracy loss. To address the aforementioned constraints, in this work, we propose EQ-ViT, an end-to-end acceleration framework with novel algorithm and architecture co-design features to enable real-time ViT acceleration on AMD Versal Adaptive Compute Acceleration Platform (ACAP). The contributions are four-fold. First, we perform in-depth kernel- level performance profiling & analysis and explain the bottlenecks for existing acceleration solutions on GPU, FPGA, and ACAP. Second, on the hardware level, we introduce a new spatial and heterogeneous accelerator architecture, EQ-ViT architec- ture. This architecture leverages the heterogeneous features of ACAP, where both FPGA and artificial intelligence engines (AIEs) coexist on the same system-on-chip (SoC). Third, On the algorithm level, we create a comprehensive quantization-aware training strategy, EQ-ViT algorithm. This strategy concurrently quantizes both weights and activations into 8-bit integers, aiming to improve accuracy rather than compromise it during quanti- zation. Notably, the method also quantizes nonlinear functions for efficient hardware implementation. Fourth, we design EQ- ViT automation framework to implement the EQ-ViT architec- ture for four different ViT applications on the AMD Versal ACAP VCK190 board, achieving accuracy improvement with 2.4%, and average speedups of 315.0x, 3.39x, 3.38x, 14.92x, 59.5x, 13.1x over computing solutions of Intel Xeon 8375C vCPU, Nvidia A10G, A100, Jetson AGX Orin GPUs, and AMD ZCU102, U250 FPGAs. The energy efficiency gains are 62.2x, 15.33x, 12.82x, 13.31x, 13.5x, 21.9x. 

Smart phones have revolutionized the availability of computing to the consumer. Recently, smart phones have been aggressively integrating artificial intelligence (AI) capabilities into their devices. The custom designed processors for the latest phones integrate incredibly capable and energy efficient graphics processors (GPUs) and tensor processors (TPUs) to accommodate this emerging AI workload and on-device inference. Unfor- tunately, smart phones are far from sustainable and have a substantial carbon footprint that continues to be dominated by environmental impacts from their manufacture and far less so by the energy required to power their operation. In this paper we explore the possibility of reversing the trend to increase the dedicated silicon dedicated to emerging application workloads in the phone. Instead we consider how in-memory processing using the DRAM already present in the phone could be used in place of dedicated GPU/TPU devices for AI inference. We explore the potential savings in embodied carbon that could be possible with this tradeoff and provide some analysis of the potential of in- memory computing to compete with these accelerators. While it may not be possible to achieve the same throughput, we suggest that the responsiveness to the user may be sufficient using in- memory computing, while both the embodied and operational carbon footprints could be improved. Our approach can save circa 10–15kgCO2e.