Bringing network device drivers into userspace

Abstract

With the advent of 10GbE/40GbE high performance NIC(Network Interface Card)s, high-performance network drivers bypassing the kernel network stack overheads have emerged. Intel Data Plane Development Kit (DPDK) is one such high-performance packet I/O framework with userspace drivers on top of Userspace I/O (UIO), which exposes device memory into userspace and delivers interrupts. However, the complex set of functionalities that today’s network drivers have to support calls for a great effort to re-implement kernel device drivers into userspace. In this work, we propose a methodology to build a high-performance userspace driver from existing kernel drivers. On top of UIO, we emulate kernel-specific functions for the userspace to make a greater percentage of kernel driver code reusable, and our novel shim interface makes a high-performance bridge between the device driver and Intel DPDK. With our emulation layer and optimized shim interface, we have successfully converted a 40GbE Mellanox driver for Intel DPDK and report 8.11 times better performance better than the original kernel driver for 64B packets.