The success of modern public/edge clouds hinges heavily on the performance of their end-host network stacks if they are to support the emerging and diverse tenants' workloads (e.g., distributed training in the cloud to fast inference at the edge). Virtual Switches (vSwitches) are vital components of this stack, providing a unified interface to enforce high-level policies on incoming packets and route them to physical interfaces, containers, or virtual machines. As performance demands escalate, there has been a shift toward offloading vSwitch processing to SmartNICs to alleviate CPU load and improve efficiency. However, existing solutions struggle to handle the growing flow rule space within the NIC, leading to high miss rates and poor scalability.

•Virtual switches optimize performance by caching multi-table lookup traversals to single-table Megaflow cache, which SmartNICs offload directly to hardware •We present Gigaflow: a multi-table sub-traversal cache for SmartNICs, designed to capture a much larger rule space using the same cache size •Open vSwitch caches traversals into Megaflow and can't share sub-traversals among traffic, making the captured rule space proportional to cache size •By caching sub-traversals into a multi-table cache, we can capture 3 orders of magnitude more rule space, attain 51% higher cache hit rate, and 31% lower end-to-end packet latency, with manageable processing overhead