fSEAD: a Composable FPGA-based Streaming Ensemble Anomaly Detection Library
Binglei Lou, David Boland, Philip H. W. Leong
TL;DR
The paper addresses the need for scalable, low-latency anomaly detection in streaming data by introducing fSEAD, a composable FPGA-based SEAD library. It combines an HLS-based Module Generator with a run-time fabric of pblocks interconnected by AXI switches and reconfigurable via Dynamic Function eXchange (DFX) to assemble diverse detector ensembles including Loda, RS-Hash, and xStream. The main contributions are the first FPGA-based SEAD framework enabling runtime composition of multiple detectors without recompilation, hardware implementations of three state-of-the-art detectors, and an open-source design demonstrating $3\times$ to $8\times$ CPU speedups with configurable trade-offs in accuracy and power. This work enables flexible, scalable hardware acceleration for real-time anomaly detection with tunable resource use and reconfiguration overhead.
Abstract
Machine learning ensembles combine multiple base models to produce a more accurate output. They can be applied to a range of machine learning problems, including anomaly detection. In this paper, we investigate how to maximize the composability and scalability of an FPGA-based streaming ensemble anomaly detector (fSEAD). To achieve this, we propose a flexible computing architecture consisting of multiple partially reconfigurable regions, pblocks, which each implement anomaly detectors. Our proof-of-concept design supports three state-of-the-art anomaly detection algorithms: Loda, RS-Hash and xStream. Each algorithm is scalable, meaning multiple instances can be placed within a pblock to improve performance. Moreover, fSEAD is implemented using High-level synthesis (HLS), meaning further custom anomaly detectors can be supported. Pblocks are interconnected via an AXI-switch, enabling them to be composed in an arbitrary fashion before combining and merging results at run-time to create an ensemble that maximizes the use of FPGA resources and accuracy. Through utilizing reconfigurable Dynamic Function eXchange (DFX), the detector can be modified at run-time to adapt to changing environmental conditions. We compare fSEAD to an equivalent central processing unit (CPU) implementation using four standard datasets, with speed-ups ranging from $3\times$ to $8\times$.
