Performance Characteristics of a Kernel-Space Packet Capture Module

摘要

This research attempts to improve the efficiency of capturing network packets to disk using commodity, general-purpose hardware and operating systems. It examines the bottlenecks between NIC and disk, implements a kernel- space capture capability to improve storage efficiency, and analyzes the performance characteristics of this approach. Results show that a kernel-space NIC-to-Disk capture module is both possible and beneficial. The proof of concept PKAP kernel-space packet capture module can capture packets to disk with a packet drop rate 8.9% less than the user-space equivalent, at a 95% confidence interval. During the high levels of disk I/O contention produced by queries for the captured data, the PKAP implementation shows a 3% reduction in CPU utilization, and overall the PKAP implementation reduces memory utilization of the capture process by 16%.