A TCP Tuning Daemon

Many high performance distributed applications require high network throughput but are able to achieve only a small fraction of the available bandwidth. A common cause of this problem is improperly tuned network settings. Tuning techniques, such as setting the correct TCP buffers and using parallel streams, are well known in the networking community, but outside the networking community they are infrequently applied. In this paper, we describe a tuning daemon that uses TCP instrumentation data from the Unix kernel to transparently tune TCP parameters for specified individual flows over designated paths. No modifications are required to the application, and the user does not need to understand network or TCP characteristics.