PointAcc: Efficient Point Cloud Accelerator

TL;DR

PointAcc is a specialized hardware accelerator that significantly improves the speed and energy efficiency of deep learning on sparse 3D point clouds, enabling real-time applications on edge devices.

Contribution

The paper introduces PointAcc, a novel accelerator design that efficiently handles sparse point cloud operations, outperforming existing hardware in speed and energy consumption.

Findings

Achieves 3.7X speedup over RTX 2080Ti GPU

Reduces energy consumption by 22X compared to GPU

Rivals prior accelerators with 100X speedup and higher accuracy

Abstract

Deep learning on point clouds plays a vital role in a wide range of applications such as autonomous driving and AR/VR. These applications interact with people in real-time on edge devices and thus require low latency and low energy. Compared to projecting the point cloud to 2D space, directly processing the 3D point cloud yields higher accuracy and lower #MACs. However, the extremely sparse nature of point cloud poses challenges to hardware acceleration. For example, we need to explicitly determine the nonzero outputs and search for the nonzero neighbors (mapping operation), which is unsupported in existing accelerators. Furthermore, explicit gather and scatter of sparse features are required, resulting in large data movement overhead. In this paper, we comprehensively analyze the performance bottleneck of modern point cloud networks on CPU/GPU/TPU. To address the challenges, we then present PointAcc, a novel point cloud deep learning accelerator. PointAcc maps diverse mapping operations onto one versatile ranking-based kernel, streams the sparse computation with configurable caching, and temporally fuses consecutive dense layers to reduce the memory footprint. Evaluated on 8 point cloud models across 4 applications, PointAcc achieves 3.7X speedup and 22X energy savings over RTX 2080Ti GPU. Co-designed with light-weight neural networks, PointAcc rivals the prior accelerator Mesorasi by 100X speedup with 9.1% higher accuracy running segmentation on the S3DIS dataset. PointAcc paves the way for efficient point cloud recognition.