On the (dis)Advantages of Programmable NICs for Network Security Services.

Emerging programmable network interface cards (a.k.a. SmartNICs) are a viable alternative to reduce the gap between network bandwidths, currently at the scale of multi-hundred Gbps, and the server CPU processing capacity. This has rapidly led to many efforts exploring SmartNICs for offloading or accelerating applications that traditionally run solely on servers (e.g., key-value stores, data analytics). Despite the success of this paradigm, the suitability of SmartNICs for running security applications, specially those that heavily rely on cryptographic operations, still remains largely unstudied. In this paper, we aim at filling this gap and provide the first in-depth analysis of current SmartNICs' crypto capabilities. Our experiments with an ARM-based multi-core SmartNIC show that the device depends heavily on architecture enhancements (e.g., cryptographic instructions and hardware accelerators) to meet server performance on crypto-workloads. Moreover, data movements between the SmartNIC and crypto-hardware accelerator cores can introduce significant overhead and make the latter ineffective, particularly for short living tasks. From a service perspective, SmartNICs can take advantage of their privileged position (i.e., closer to client devices than server CPUs) to speed up crypto-based functions. However, the SmartNIC benefits can be easily outweighed if the application is too much data-intensive or includes several non-crypto tasks.