1.\" $NetBSD: kttcp.4,v 1.4 2006/12/28 11:44:19 wiz 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.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the NetBSD 17.\" Foundation, Inc. and its contributors. 18.\" 4. Neither the name of The NetBSD Foundation nor the names of its 19.\" contributors may be used to endorse or promote products derived 20.\" from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32.\" POSSIBILITY OF SUCH DAMAGE. 33.\" 34.Dd December 2, 2006 35.Dt KTTCP 4 36.Os 37.Sh NAME 38.Nm kttcp 39.Nd kernel support for testing network throughput 40.Sh SYNOPSIS 41.Cd "pseudo-device kttcp" 42.Sh DESCRIPTION 43This driver provides kernel support for testing network 44throughput from the perspective of the kernel. 45It is similar in spirit to the classic ttcp network benchmark 46program, the main difference being that with kttcp, the kernel is 47the source and sink of the data. 48.Pp 49Testing like this is useful for a few reasons: 50.Bl -enum 51.It 52This allows us to know what kind of performance we can 53expect from network applications that run in the kernel 54space, such as the NFS server or the NFS client. 55These applications don't have to move the data to/from userspace, 56and so benchmark programs which run in userspace don't give us an 57accurate model. 58.It 59Since data received is just thrown away, the receiver is very fast. 60This can provide better exercise for the sender at the other end. 61.It 62Since the 63.Nx 64kernel currently uses a run-to-completion 65scheduling model, kttcp provides a benchmark model where 66preemption of the benchmark program is not an issue. 67.El 68.Sh SEE ALSO 69.Pa pkgsrc/benchmarks/kttcp , 70.Pa pkgsrc/benchmarks/ttcp 71