ceph/src/spdk/dpdk/doc/guides/nics/kni.rst

   1 ..  SPDX-License-Identifier: BSD-3-Clause
   2     Copyright(c) 2017 Intel Corporation.
   3
   4 KNI Poll Mode Driver
   5 ======================
   6
   7 KNI PMD is wrapper to the :ref:`librte_kni <kni>` library.
   8
   9 This PMD enables using KNI without having a KNI specific application,
  10 any forwarding application can use PMD interface for KNI.
  11
  12 Sending packets to any DPDK controlled interface or sending to the
  13 Linux networking stack will be transparent to the DPDK application.
  14
  15 To create a KNI device ``net_kni#`` device name should be used, and this
  16 will create ``kni#`` Linux virtual network interface.
  17
  18 There is no physical device backend for the virtual KNI device.
  19
  20 Packets sent to the KNI Linux interface will be received by the DPDK
  21 application, and DPDK application may forward packets to a physical NIC
  22 or to a virtual device (like another KNI interface or PCAP interface).
  23
  24 To forward any traffic from physical NIC to the Linux networking stack,
  25 an application should control a physical port and create one virtual KNI port,
  26 and forward between two.
  27
  28 Using this PMD requires KNI kernel module be inserted.
  29
  30
  31 Usage
  32 -----
  33
  34 EAL ``--vdev`` argument can be used to create KNI device instance, like::
  35
  36         testpmd --vdev=net_kni0 --vdev=net_kn1 -- -i
  37
  38 Above command will create ``kni0`` and ``kni1`` Linux network interfaces,
  39 those interfaces can be controlled by standard Linux tools.
  40
  41 When testpmd forwarding starts, any packets sent to ``kni0`` interface
  42 forwarded to the ``kni1`` interface and vice versa.
  43
  44 There is no hard limit on number of interfaces that can be created.
  45
  46
  47 Default interface configuration
  48 -------------------------------
  49
  50 ``librte_kni`` can create Linux network interfaces with different features,
  51 feature set controlled by a configuration struct, and KNI PMD uses a fixed
  52 configuration:
  53
  54     .. code-block:: console
  55
  56         Interface name: kni#
  57         force bind kernel thread to a core : NO
  58         mbuf size: MAX_PACKET_SZ
  59
  60 KNI control path is not supported with the PMD, since there is no physical
  61 backend device by default.
  62
  63
  64 PMD arguments
  65 -------------
  66
  67 ``no_request_thread``, by default PMD creates a phtread for each KNI interface
  68 to handle Linux network interface control commands, like ``ifconfig kni0 up``
  69
  70 With ``no_request_thread`` option, pthread is not created and control commands
  71 not handled by PMD.
  72
  73 By default request thread is enabled. And this argument should not be used
  74 most of the time, unless this PMD used with customized DPDK application to handle
  75 requests itself.
  76
  77 Argument usage::
  78
  79         testpmd --vdev "net_kni0,no_request_thread=1" -- -i
  80
  81
  82 PMD log messages
  83 ----------------
  84
  85 If KNI kernel module (rte_kni.ko) not inserted, following error log printed::
  86
  87         "KNI: KNI subsystem has not been initialized. Invoke rte_kni_init() first"
  88
  89
  90 PMD testing
  91 -----------
  92
  93 It is possible to test PMD quickly using KNI kernel module loopback feature:
  94
  95 * Insert KNI kernel module with loopback support:
  96
  97     .. code-block:: console
  98
  99         insmod build/kmod/rte_kni.ko lo_mode=lo_mode_fifo_skb
 100
 101 * Start testpmd with no physical device but two KNI virtual devices:
 102
 103     .. code-block:: console
 104
 105         ./testpmd --vdev net_kni0 --vdev net_kni1 -- -i
 106
 107     .. code-block:: console
 108
 109         ...
 110         Configuring Port 0 (socket 0)
 111         KNI: pci: 00:00:00       c580:b8
 112         Port 0: 1A:4A:5B:7C:A2:8C
 113         Configuring Port 1 (socket 0)
 114         KNI: pci: 00:00:00       600:b9
 115         Port 1: AE:95:21:07:93:DD
 116         Checking link statuses...
 117         Port 0 Link Up - speed 10000 Mbps - full-duplex
 118         Port 1 Link Up - speed 10000 Mbps - full-duplex
 119         Done
 120         testpmd>
 121
 122 * Observe Linux interfaces
 123
 124     .. code-block:: console
 125
 126         $ ifconfig kni0 && ifconfig kni1
 127         kni0: flags=4098<BROADCAST,MULTICAST>  mtu 1500
 128                 ether ae:8e:79:8e:9b:c8  txqueuelen 1000  (Ethernet)
 129                 RX packets 0  bytes 0 (0.0 B)
 130                 RX errors 0  dropped 0  overruns 0  frame 0
 131                 TX packets 0  bytes 0 (0.0 B)
 132                 TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
 133
 134         kni1: flags=4098<BROADCAST,MULTICAST>  mtu 1500
 135                 ether 9e:76:43:53:3e:9b  txqueuelen 1000  (Ethernet)
 136                 RX packets 0  bytes 0 (0.0 B)
 137                 RX errors 0  dropped 0  overruns 0  frame 0
 138                 TX packets 0  bytes 0 (0.0 B)
 139                 TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
 140
 141
 142 * Start forwarding with tx_first:
 143
 144     .. code-block:: console
 145
 146         testpmd> start tx_first
 147
 148 * Quit and check forwarding stats:
 149
 150     .. code-block:: console
 151
 152         testpmd> quit
 153         Telling cores to stop...
 154         Waiting for lcores to finish...
 155
 156         ---------------------- Forward statistics for port 0  ----------------------
 157         RX-packets: 35637905       RX-dropped: 0             RX-total: 35637905
 158         TX-packets: 35637947       TX-dropped: 0             TX-total: 35637947
 159         ----------------------------------------------------------------------------
 160
 161         ---------------------- Forward statistics for port 1  ----------------------
 162         RX-packets: 35637915       RX-dropped: 0             RX-total: 35637915
 163         TX-packets: 35637937       TX-dropped: 0             TX-total: 35637937
 164         ----------------------------------------------------------------------------
 165
 166         +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++
 167         RX-packets: 71275820       RX-dropped: 0             RX-total: 71275820
 168         TX-packets: 71275884       TX-dropped: 0             TX-total: 71275884
 169         ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 170