aRFS+: A New Flow Steering Scheme for High Network Performance

Jaehyun Park, Jaehyun Hwang

http://doi.org/10.5626/JOK.2024.51.5.397

Recent studies indicate that a significant portion of central processing unit (CPU) usage in network stack processing is attributed to the transfer of data between kernel and user spaces. Direct Cache Access (DCA) has been recognized to enhance data copy efficiency by allowing applications to perform data copy operations utilizing L3 caches. However, current flow steering mechanisms lack awareness of caches; they often employ random selection methods or allocate processing tasks to cores based on the location of corresponding applications subsequently resulting in suboptimal throughput. To address this issue, in this paper, we propose a novel flow steering scheme named aRFS+. The three key ideas of aRFS+ are as follows. First, we dynamically allocated network applications to the DCA-capable NUMA node, enabling them to exploit DCA advantages during data copy operations. Second, we decouple application cores from network processing cores to maximize the benefits of multicore environments. Incoming packets are steered to a CPU distinct from the application core but situated within the same NUMA node. Third, we introduce an optimization technique that significantly mitigates the overhead associated with memory management. Our experimental evaluations demonstrated that aRFS+ substantially improved the overall throughput, with an enhancement of up to 60% compared to existing schemes.