In this thesis, a zero-copy TCP server is designed and implemented in order to get higher performance compared with the conventional Internet servers. Our work includes two major contributions. First, two main functions are separated in an Internet server: TCP/IP processing and application-level processing. Then, each function is distributed to the dedicated server: zero-copy TCP server and application host. The VIA technology is applied for the low-overhead communication between zero-copy TCP server and application host. Second, a redundant data copy is reduced in the zero-copy TCP server. The zero-copy TCP server is responsible for receiving TCP/IP packets from the Internet clients; then the application-layer data are collected and transferred to the application server using VIA. While relaying data in the zero-copy TCP server, many redundant copy operations are happened between user-space and kernel-space of the conventional operating system. Therefore, our zero-copy TCP server provides a shared memory area, which can be directly accessed from the user-space and the kernel-space. The shared memory area is implemented using the HRAM (High address RAM) technology. The zero-copy TCP server and a simple multi-threaded web server are implemented on Linux 2.4.21. The experimental results show that our zero-copy TCP server can boost up the performance of a traditional web server upto 40%.
본 논문에서는 기존의 인터넷 서버보다 성능 향상을 위해 제로카피 TCP 서버를 제안하고 구현하였다. 본 논문에서는 기존의 인터넷 서버의 TCP/IP 프로세싱과 응용 프로그램을 분리하여 각각의 프로세싱은 제로카피 TCP 서버와 응용 서버에서만 수행되도록 한다. VIA는 제로카피 TCP 서버의 응용 서버간의 통신을 위해 사용되며 TCP/IP의 오버헤드를 줄이기 위해서 제로카피 TCP 서버에서는 불필요한 데이터 복사를 없앴다. 이러한 두가지 기술의 결합으로 본 논문에서 제안한 제로카피 TCP 서버를 사용하면 기존의 인터넷 서버보다 최대 40%의 성능 향상을 보인다.
