FPGA accelerated packet capture with eBPF : Performance considerations of using SoC FPGA accelerators for packet capturing.

Abstract: With the rise of the Internet of Things and the proliferation of embedded devices equipped with an accelerator arose a need for efficient resource utilization. Hardware acceleration is a complex topic that requires specialized domain knowledge about the platform and different trade-offs that have to be made, especially in the area of power consumption. Efficient work offloading strives to reduce or at least maintain the total power consumption of the system. Offloading packet capturing is usually done in more powerful devices, hence scarce research is present concerning network packet acceleration in embedded devices. The thesis focuses on accelerating networking packets utilizing a Field Programmable Gate Array in an embedded Linux System. The solution is based on a custom Linux distribution assembled using the Buildroot tool, specially configured and patched Linux kernel, uboot bootloader, and the programmable logic for packet acceleration. The system is evaluated on a De0-Nano System on Chip development board through modifications to burst lengths, packet sizes, and programmable logic clock frequency. Metrics include packet capturing time, time per packet, and consumed power. Finally, the results are contrasted with baseline embedded Linux packet processing by inspection of a packet’s path through the kernel. Collected results provide a deeper understanding of the packet acceleration problem in embedded devices and the resultant system gives a solid starting point for possible extensions such as packet filtering. Key findings include an improvement in packet processing speed as the clock frequency and burst length are increased while maintaining power consumption. Additionally, the solution performs better when the packet sizes are above 64 bytes as the overhead of additional logic necessary for their processing is compensated. The project is also found to be significantly faster than regular in kernel processing with the caveat of providing just packet capturing whereas Linux contains a full network stack.