90 lines
3.0 KiB
Groff
90 lines
3.0 KiB
Groff
.\"
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.\" Copyright (c) 2016 Alexander Motin <mav@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 2, 2017
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.Dt IF_NTB 4
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.Os
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.Sh NAME
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.Nm if_ntb
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.Nd Virtual Ethernet interface for Non-Transparent Bridges
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.Sh SYNOPSIS
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To compile this driver into your kernel,
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place the following lines in your kernel configuration file:
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.Bd -ragged -offset indent
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.Cd "device ntb"
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.Cd "device ntb_transport"
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.Cd "device if_ntb"
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.Ed
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.Pp
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Or, to load the driver as a module at boot, place the following line in
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.Xr loader.conf 5 :
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.Bd -literal -offset indent
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if_ntb_load="YES"
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.Ed
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.Pp
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The following tunables are settable from the
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.Xr loader 8 :
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.Bl -ohang
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.It Va hw.if_ntb.num_queues
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Limits maximal number of queues per interface.
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Default is unlimited.
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.El
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.Sh DESCRIPTION
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The
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.Nm
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driver attaches on top of the
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.Xr ntb_transport 4
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driver to utilize one or more of its packet queues to create virtual
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Ethernet network interface between the systems.
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Typical MTU for the interface is about 64KB to reduce overhead.
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Default MAC address for the interface is randomly generated.
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.Pp
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The
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.Nm
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driver does not implement any real hardware offload, but since PCIe link is
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protected by CRC32, in some situations it may be possible to save some CPU
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cycles by enabling fake checksum offload on both link sides via setting
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.Cm rxcsum
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and
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.Cm txcsum
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interface options.
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.Sh SEE ALSO
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.Xr ntb_transport 4
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm
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driver was developed by Intel and originally written by
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.An Carl Delsey Aq Mt carl@FreeBSD.org .
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Later improvements were done by
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.An Conrad E. Meyer Aq Mt cem@FreeBSD.org
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and
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.An Alexander Motin Aq Mt mav@FreeBSD.org .
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.Sh BUGS
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Linux supports only one queue per interface, so manual configuration
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may be required for compatibility.
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