SCENIC: Stream Computation-Enhanced SmartNIC

TL;DR

SCENIC is an open-source SmartNIC that treats the NIC datapath as a stream computation platform, enabling high-performance, customizable network processing integrated with existing datacenter infrastructure.

Contribution

The paper introduces SCENIC, a novel SmartNIC design that combines high bandwidth, programmability, and integration with Linux, bridging the gap between commercial and research SmartNICs.

Findings

SCENIC achieves 200G network throughput with integrated TCP/IP and RDMA stacks.

It supports flexible data processing with on-datapath Stream Compute Units (SCUs).

Performance matches commercial SmartNICs and enables diverse use cases.

Abstract

Although modern, AI-centric datacenters heavily rely on SmartNICs, existing devices impose a hard trade-off. Commercial SmartNICs provide high bandwidth and easy software integration, but offer limited support for customization and data processing offload. In contrast, research SmartNICs often suffer from low bandwidth, limited functionality, and poor software compatibility -- to the point that many are not actual NICs in a technical sense. This gap can be closed by treating the NIC datapath as a first-class stream computation substrate with shared hardware/software abstractions for a tight co-design of infrastructure and applications. To demonstrate this, we introduce SCENIC, an open-source datacenter SmartNIC. SCENIC implements a 200G network datapath over offloaded TCP/IP and RDMA stacks, as well as a fallback path for processing arbitrary network traffic. On top of the network logic, SCENIC combines on-datapath Stream Compute Units (SCUs) for data processing and embedded ARM cores for flexible control path manipulation with direct access to GPUs and SSDs. SCENIC is fully integrated with the OS, exposing native Linux network and RDMA verb interfaces, making the programmable datapath transparent to existing applications while enabling control of, e.g., user-defined offloads and programmable congestion control. SCENIC's performance matches commercial platforms, and we show its versatility through several use cases such as offloaded collective communication and network-to-GPU hash-based data partitioning.