accept()able Strategies for Improving Web Server Performance

This paper evaluates techniques for improving the performance of three architecturally different web servers. We study strategies for effectively accepting incoming connections under conditions of high load. Our experimental evaluation shows that the method used to accept new connection requests can significantly impact server performance. By modifying each server's accept strategy, we improve the performance of the kernel-mode TUX server, the multi-threaded Knot server and the event-driven server. Under two different workloads, we improve the throughput of these servers by as much as 19% - 36% for TUX, 0% - 32% for Knot, and 39% - 71% for the server. Interestingly, the performance improvements realized by the user-mode server allow it to obtain performance that rivals an unmodified TUX server.