FlowValve+: Multi-Queue Packet Scheduling Framework on SoC-Based SmartNICs

Enforcing scheduling policies with software schedulers at end-hosts leads to high CPU consumption, low throughput, and inaccuracies. To address these issues, offloading packet schedulers to the network interface card presents a promising research direction. However, existing attempts suffer from inflexible on-NIC scheduling that cannot execute complex hierarchies of network policies. In this article, we propose FlowValve⁺, a general framework for multi-queue packet scheduling on SoC-based SmartNICs. The key insight behind FlowValve⁺ is to abstract the inherent queueing system as a single FIFO queue and perform specialized tail drop to mix the FIFO queue with expected flow proportions. FlowValve⁺ leverages hardware accelerations to produce high throughput while substantially reducing CPU and memory usage on end-hosts. We prototype FlowValve⁺ on Netronome Agilio 40GbE and NVIDIA Bluefield-2 100GbE SmartNICs to demonstrate its ability to accurately enforce network policies while driving TCP traffic at 40 Gbps and 80 Gbps on both platforms, respectively. Moreover, FlowValve⁺ can save two CPU cores compared to DPDK packet schedulers.