USENIX Conference Policies
Scalable Kernel Performance for Internet Servers Under Realistic Loads
Gaurav Banga, Rice University; Jeffrey C. Mogul, Digital Equipment Corp., Western Research Lab
UNIX Internet servers with an event-driven architecture often perform poorly under real workloads, even if they perform well under laboratory benchmarking conditions. We investigated the poor performance of event-driven servers. We found that the delays typical in wide-area networks cause busy servers to manage a large number of simultaneous connections. We also observed that the select system call implementation in most UNIX kernels scales poorly with the number of connections being managed by a process. The UNIX algorithm for allocating file descriptors also scales poorly. These algorithmic problems lead directly to the poor performance of event-driven servers.
We implemented scalable versions of the select system call and the descriptor allocation algorithm. This led to an improvement of up to 58% in Web proxy and Web server throughput, and dramatically improved the scalability of the system.
author = {Gaurav Banga and Jeffrey C. Mogul},
title = {Scalable Kernel Performance for Internet Servers Under Realistic Loads},
booktitle = {1998 USENIX Annual Technical Conference (USENIX ATC 98)},
year = {1998},
address = {New Orleans, LA},
url = {https://www.usenix.org/conference/1998-usenix-annual-technical-conference/scalable-kernel-performance-internet-servers},
publisher = {USENIX Association},
month = jun
}