MegaTurbo: A Scalable FPGA-based Engine for MegaFlow Classifier in Open vSwitch (ACM/SIGDA FPGA, 2026)

  • Authors: Sheng Lan, Ying Li, Zhongxian Liang, Wenjun Li*, Yao Xin*, Ying Wan, Hui Li, and Weizhe Zhang
  • Sheng Lan, Ying Li, and Zhongxian Liang are student authors, and they conducted this work under the supervision of their Ph.D. advisor as well as the corresponding author of this paper: Wenjun Li. Yao Xin is the co-corresponding author of this paper.

Abstract

Open vSwitch (OVS) is a key component in cloud and data center networks, yet its MegaFlow classifier imposes significant CPU overhead. Existing SmartNIC-based acceleration approaches for the MegaFlow classifier typically employ simplistic hardware offloading techniques, which exhibit limited scalability for dynamic, large-scale flow tables. Motivated by these challenges, we argue that a hardware accelerator specifically tailored for the MegaFlow classifier is necessary, forming the basis of our FPGA-based solution, MegaTurbo. The core innovations of MegaTurbo are threefold: (1) a scalable and hardware-friendly decision-tree based packet classification algorithm, specifically optimized for the structure of MegaFlow rules; (2) a novel hardware architecture incorporating multiple pipelined matching engines, designed to process multiple decision trees generated by the software algorithm in parallel; and (3) a heterogeneous framework composed of CPU and FPGA, which can work together to support online rule updates, with little and bounded impact on rule searching. Experimental results on a Xilinx Virtex UltraScale+ FPGA demonstrate that MegaTurbo achieves a sustained classification throughput of 500 MPPS while supporting dynamic rule updates at 300-500 KUPS on 100K-scale rulesets. These results not only validate the effectiveness of our domain-specific co-design approach, but also highlight the potential of FPGA-based SmartNICs to address the performance bottlenecks of software switches in large-scale cloud and data center networks.

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News

2025.11.19: The website of MegaTurbo is under construction and will be finished soon.

Contact

E-mail: wenjunli@pku.org.cn.