arXiv subjects

Herman Lam

Publications and source records attributed to Herman Lam.

3 recordsLinked to original sources

arXiv2026

L-PCN: A Point Cloud Accelerator Exploiting Spatial Locality through Octree-based Islandization

Existing Point Cloud Networks (PCNs) have proven to achieve great success in many point cloud tasks such as object part segmentation, shape classification, and so on. The most popular point-based PCNs are usually composed of two sequential steps: Data Structuring (DS) and Feature Computation (FC). In this paper, we first describe an important characteristic of the PCN-specific DS step that has not been addressed in existing PCN accelerators: the spatial locality resulting from overlapping points of the gathered point subsets. Using algorithm-hardware co-design, L-PCN (Locality-aware PCN) proposes two novel techniques to exploit this characteristic to reduce the large amount of repetitive operations in the overall PCN. The first of which is a point cloud partitioning technique, Octree-based Islandization. Using Octree-based adjacency gathering, a point cloud is partitioned into islands in L-PCN, where the point subsets inside the same island exhibit a strong spatial correlation. After partitioning, L-PCN performs the rest of PCN steps at the granularity of islands. The second method of L-PCN is scheduling the intra-island computation with a Hub-based Scheduling to exploit the intra-island data reuse by dynamically caching, updating, and reusing the repeated data. The two methods are implemented in an Islandization Unit, which can be seamlessly integrated into standard PCN workflow. Our evaluation shows that based on our methods for exploiting spatial locality, L-PCN achieves a theoretical reduction in feature fetching ranging from 55.2% to 93.8% and in feature computation ranging from 45.4% to 80.6% during the PCN process. For experimentation, prototype L-PCN accelerators are implemented on the Intel Arria 10 GX FPGA. Experimental results prove that with the Islandization Unit as a plug-in, state-of-the-art PCN accelerators can achieve an additional speedup ranging from 1.2x to 3.2x.

cs.AR↗

arXiv2025

RISCBench: Benchmarking RISC-V Orchestration Efficiency in FPGA and FPGA-Like Computing Engines

Heterogeneous systems increasingly rely on RISC-V cores as orchestration engines to manage data movement, synchronization, and scheduling across accelerators and reconfigurable fabrics. Conventional performance metrics, such as FLOPs, TOPS/W, or energy per operation, do not capture orchestration efficiency, even though it often dictates sustained system behavior. This gap is increasingly relevant as systems evolve toward tightly coupled heterogeneous fabrics and co-packaged accelerators, where control-plane behavior determines whether these platforms achieve their promised performance. We present RISCBench, a kernel benchmark suite and open methodology for quantifying orchestration efficiency. RISCBench introduces the Sustained Instantaneous Throughput (SIT) metric, which accumulates instantaneous throughput over near-aggregate execution intervals, capturing sustained efficiency beyond peak rates. The methodology is evaluated across representative platforms spanning soft and hard RISC-V orchestration engines, including FPGA-based prototyping and accelerator-class implementations. Results highlight synchronization and data residency driven tradeoffs that limit realized throughput beyond peak performance, motivating SIT as a practical, platform-independent descriptor for evaluating orchestration efficiency in heterogeneous systems and AI inference applications.

cs.AR↗

arXiv2025

HgPCN: A Heterogeneous Architecture for E2E Embedded Point Cloud Inference

Point cloud is an important type of geometric data structure for many embedded applications such as autonomous driving and augmented reality. Current Point Cloud Networks (PCNs) have proven to achieve great success in using inference to perform point cloud analysis, including object part segmentation, shape classification, and so on. However, point cloud applications on the computing edge require more than just the inference step. They require an end-to-end (E2E) processing of the point cloud workloads: pre-processing of raw data, input preparation, and inference to perform point cloud analysis. Current PCN approaches to support end-to-end processing of point cloud workload cannot meet the real-time latency requirement on the edge, i.e., the ability of the AI service to keep up with the speed of raw data generation by 3D sensors. Latency for end-to-end processing of the point cloud workloads stems from two reasons: memory-intensive down-sampling in the pre-processing phase and the data structuring step for input preparation in the inference phase. In this paper, we present HgPCN, an end-to-end heterogeneous architecture for real-time embedded point cloud applications. In HgPCN, we introduce two novel methodologies based on spatial indexing to address the two identified bottlenecks. In the Pre-processing Engine of HgPCN, an Octree-Indexed-Sampling method is used to optimize the memory-intensive down-sampling bottleneck of the pre-processing phase. In the Inference Engine, HgPCN extends a commercial DLA with a customized Data Structuring Unit which is based on a Voxel-Expanded Gathering method to fundamentally reduce the workload of the data structuring step in the inference phase.

cs.AR↗