Design and Implementation of an Efficient and Configurable Instrument Platform for Linux Network Protocol Stack

• Main Authors: Min-Feng Tsao, 曹敏峰
• Other Authors: Chien-Chao Tseng
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/78788990241618975689

碩士 === 國立交通大學 === 資訊科學與工程研究所 === 96 === Due to the continuously increasing demands for various applications of embedded networking and communication devices, the industry and academic both have spent a great amount of research efforts on developing new and better embedded products. In order to develop a high efficient communication system for embedded networking and communication devices, we need to consider not only the basic network accessibility but also the critical performance metrics, such as transmission delays, response times, and packet losses, of embedded devices. Therefore, how to measure various delays, response times and packet losses becomes the major research issue in embedded networking systems. Many network sniffer tools exist for researchers to intercept and analyze network packets. However, the current network sniffer tools can capture only the “external” networking behaviors of communication protocols but not the effects of network kernel subsystems on communications. In other words, they merely intercept network packets for analysis but do not provide any vehicles for the analysis of kernel effects on communications. Therefore, this thesis plans to design and develop a platform that can help researchers to investigate the integrated effects of both the internal behavior of a kernel subsystem and the external behavior of the protocol packet exchanges. This thesis focuses on analyzing the behavior of network communication in Linux kernel at first. Then we develop a platform that can record related information about the important or key functions in Linux network protocol stack. With the recorded information, we can analyze to the networking capabilities and identify the bottlenecks of embedded networking and communication devices. Consequently we can try to reduce the packet transmitting/receiving delays and improve the overall performance of the network protocol stack. The goal of this thesis aims to develop an efficient and configurable instrument platform for Linux network protocol stack. We first present a naive approach that adopts the basic and intuitional methods in the design of this platform. By presenting the naive approach, we can introduce the concepts, implementation methods and design considerations of kernel patching. We then describe the concepts and design of our configurable instrument platform. The architecture of the platform consists of four basic components: (1) Linux Kernel Patching, (2) Instrument Modules, (3) Instrument Configuration Interface, and (4) Log File Generator and Analyzer. With these four modules, a user can configure instrument profile dynamically, that is at runtime and without recompilation, to trace the kernel behaviors the user is interested at. Furthermore, with the ingenious design of the Instrument Module, our platform can trace kernel functions and record kernel events with just a slightly overhead. Finally, we use real network protocols in measuring the performance of Linux Kernel Patching mechanisms and compare the effectiveness of our approach with the naive approach. The results show that our configurable instrument platform introduces only negligible overhead, and is much superior to the naive approach.