1.\" $NetBSD: kttcp.4,v 1.5 2008/04/30 13:10:54 martin Exp $ 2.\" 3.\" Copyright (c) 2003 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd December 2, 2006 28.Dt KTTCP 4 29.Os 30.Sh NAME 31.Nm kttcp 32.Nd kernel support for testing network throughput 33.Sh SYNOPSIS 34.Cd "pseudo-device kttcp" 35.Sh DESCRIPTION 36This driver provides kernel support for testing network 37throughput from the perspective of the kernel. 38It is similar in spirit to the classic ttcp network benchmark 39program, the main difference being that with kttcp, the kernel is 40the source and sink of the data. 41.Pp 42Testing like this is useful for a few reasons: 43.Bl -enum 44.It 45This allows us to know what kind of performance we can 46expect from network applications that run in the kernel 47space, such as the NFS server or the NFS client. 48These applications don't have to move the data to/from userspace, 49and so benchmark programs which run in userspace don't give us an 50accurate model. 51.It 52Since data received is just thrown away, the receiver is very fast. 53This can provide better exercise for the sender at the other end. 54.It 55Since the 56.Nx 57kernel currently uses a run-to-completion 58scheduling model, kttcp provides a benchmark model where 59preemption of the benchmark program is not an issue. 60.El 61.Sh SEE ALSO 62.Pa pkgsrc/benchmarks/kttcp , 63.Pa pkgsrc/benchmarks/ttcp 64