Tools and Techniques to debug OVS Hardware Offload

Speaker: Balazs Nemeth, Red Hat, Inc.

With the increasingly demanding network load in today's data centers, offloading network processing to the hardware has become an invaluable technique to free up CPU resources. One of the main building blocks is Linux Connection Tracking (CT) and Traffic Control (TC) which is designed to be offloaded to the hardware in a transparent way. The flip side of this transparency is that it may be difficult to assess if offload succeeds. Therefore, this talk outlines basic steps and troubleshooting techniques to determine if packets and flows are hitting the hardware, or if execution falls back to software paths. After a brief introduction to hardware offload, we'll describe the tools and commands that we've found to be useful to pinpoint issues. While these are mostly hardware agnostic, we'll discuss how they work in conjunction with a CX-5/6 smart-nic and a Bluefield-2 DPU.