Scotch: Generating FPGA-Accelerators for Sketching at Line Rate

Sketching algorithms are a powerful tool for single-pass data summarization. Their numerous applications include approximate query processing, machine learning, and large-scale network monitoring. In the presence of high-bandwidth interconnects or in-memory data, the throughput of summary maintenance over input data becomes the bottleneck. While FPGAs have shown admirable throughput and energy-efficiency for data processing tasks, developing FPGA accelerators requires a sophisticated hardware design and expensive manual tuning by an expert. We propose Scotch, a novel system for accelerating sketch maintenance using FPGAs. Scotch provides a domain-specific language for the user-friendly, high-level definition of a broad class of sketching algorithms. A code generator performs the heavy-lifting of hardware description, while an auto-tuning algorithm optimizes the summary size. Our evaluation shows that FPGA accelerators generated by Scotch outperform CPU-and GPU-based sketching by up to two orders of magnitude in terms of throughput and up to a factor of five in terms of energy efficiency.