ecoNIC: SmartNIC-assisted power management for networking workloads in Linux servers

Improving the sustainability and energy efficiency of compute resources in next-generation networks is crucial to cope with the ever-growing computing demand while maintaining manageable energy consumption in the processing nodes of the network infrastructure. Simultaneously, critical connected applications, such as autonomous driving, require a high level of service quality in terms of available throughput and achievable latencies. This demands considerable responsiveness from the compute resources and renders power management a challenging task. Existing solutions are not sufficiently adapted to the requirements and characteristics of such applications, making them either responsive but not very efficient, or efficient but unsuitable to provide the required service quality for critical tasks. We propose ecoNIC, a concept for energy-efficient network processing that combines an RSS-based hardware load balancer for SmartNICs with an adaptive Dynamic Voltage and Frequency Scaling (DVFS) governor. ecoNIC efficiently pins flow priorities to CPU core clusters, reducing the workload of selected cores in the process, and dynamically adjusts their clock speed to exploit freed- up capacities and save energy. We implement ecoNIC as an FPGA-prototype and integrate the DVFS governor into the Linux kernel. The experimental evaluation shows that significant energy savings can be achieved, while the employed priority-pinning ensures low tail latencies for critical traffic. Without sacrificing an increase in high-priority tail latencies, energy savings of 62% are possible. Further relaxation of the latency constraints allows for energy savings of up to 88%.