PMDlink – Bridging the Gap Between DPDK and Hardware Packet Processing

Abstract

Software networking functions flexibly implement packet processing, but performance is lacking compared to purpose built hardware. To address this, commodity NICs execute packet processing in hardware, improving performance, however their fixed-function design restricts the features which can be offloaded to hardware. One particular challenge is to implement HQoS, which manages traffic by enforcing QoS requirements at multiple levels, maintaining thousands of queues and applying rate limits. In this work, we combine DPDK based user-space packet processing with hardware offloaded packet processing on commodity NICs, by integrating DPDK with Linux switchdev, thus combining software flexibility and hardware acceleration. We propose PMDlink, a side-channel API enabling direct hardware control via DPDK’s PMD, exposing advanced packet processing features without major driver modifications. Our preliminary results highlight the benefits of hardware offloading by showing the combined hardware-offloaded HQoS functions and DPDK. Future work will refine PMDlink as a modular interface, to better expose NIC capabilities to DPDK, and to program more complex scheduling profiles.