.. code-block:: console
- # insmod kmod/rte_kni.ko
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko
.. _kni_loopback_mode:
.. code-block:: console
- # insmod kmod/rte_kni.ko lo_mode=lo_mode_fifo
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko lo_mode=lo_mode_fifo
The ``lo_mode_fifo`` loopback option will loop back ring enqueue/dequeue
operations in kernel space.
.. code-block:: console
- # insmod kmod/rte_kni.ko lo_mode=lo_mode_fifo_skb
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko lo_mode=lo_mode_fifo_skb
The ``lo_mode_fifo_skb`` loopback option will loop back ring enqueue/dequeue
operations and sk buffer copies in kernel space.
.. code-block:: console
- # insmod kmod/rte_kni.ko kthread_mode=single
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko kthread_mode=single
This mode will create only one kernel thread for all KNI interfaces to
receive data on the kernel side. By default, this kernel thread is not
.. code-block:: console
- # insmod kmod/rte_kni.ko kthread_mode=multiple
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko kthread_mode=multiple
This mode will create a separate kernel thread for each KNI interface to
receive data on the kernel side. The core affinity of each ``kni_thread``
.. code-block:: console
- # insmod kmod/rte_kni.ko carrier=on
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko carrier=on
To set the default carrier state to *off*:
.. code-block:: console
- # insmod kmod/rte_kni.ko carrier=off
+ # insmod <build_dir>/kernel/linux/kni/rte_kni.ko carrier=off
If the ``carrier`` parameter is not specified, the default carrier state
of KNI interfaces will be set to *off*.
-------------------------
Before any KNI interfaces can be created, the ``rte_kni`` kernel module must
-be loaded into the kernel and configured withe ``rte_kni_init()`` function.
+be loaded into the kernel and configured with the ``rte_kni_init()`` function.
The KNI interfaces are created by a DPDK application dynamically via the
``rte_kni_alloc()`` function.
user to specify the interface name, set the MTU size, set an explicit or
random MAC address and control the affinity of the kernel Rx thread(s)
(both single and multi-threaded modes).
+By default the KNI sample example gets the MTU from the matching device,
+and in case of KNI PMD it is derived from mbuf buffer length.
The ``struct rte_kni_ops`` structure contains pointers to functions to
handle requests from the ``rte_kni`` kernel module. These functions
``config_promiscusity``:
- Called when the user changes the promiscusity state of the KNI
+ Called when the user changes the promiscuity state of the KNI
interface. For example, when the user runs ``ip link set promisc
[on|off] dev <ifaceX>``. If the user sets this callback function to
NULL, but sets the ``port_id`` field to a value other than -1, a default
will be called which calls ``rte_eth_promiscuous_<enable|disable>()``
on the specified ``port_id``.
+``config_allmulticast``:
+
+ Called when the user changes the allmulticast state of the KNI interface.
+ For example, when the user runs ``ifconfig <ifaceX> [-]allmulti``. If the
+ user sets this callback function to NULL, but sets the ``port_id`` field to
+ a value other than -1, a default callback handler in the rte_kni library
+ ``kni_config_allmulticast()`` will be called which calls
+ ``rte_eth_allmulticast_<enable|disable>()`` on the specified ``port_id``.
+
In order to run these callbacks, the application must periodically call
the ``rte_kni_handle_request()`` function. Any user callback function
registered will be called directly from ``rte_kni_handle_request()`` so
The KNI interfaces can be deleted by a DPDK application with
``rte_kni_release()``. All KNI interfaces not explicitly deleted will be
-deleted when the the ``/dev/kni`` device is closed, either explicitly with
+deleted when the ``/dev/kni`` device is closed, either explicitly with
``rte_kni_close()`` or when the DPDK application is closed.
DPDK mbuf Flow
-----------------
On the DPDK RX side, the mbuf is allocated by the PMD in the RX thread context.
-This thread will enqueue the mbuf in the rx_q FIFO.
+This thread will enqueue the mbuf in the rx_q FIFO,
+and the next pointers in mbuf-chain will convert to physical address.
The KNI thread will poll all KNI active devices for the rx_q.
If an mbuf is dequeued, it will be converted to a sk_buff and sent to the net stack via netif_rx().
-The dequeued mbuf must be freed, so the same pointer is sent back in the free_q FIFO.
+The dequeued mbuf must be freed, so the same pointer is sent back in the free_q FIFO,
+and next pointers must convert back to virtual address if exists before put in the free_q FIFO.
The RX thread, in the same main loop, polls this FIFO and frees the mbuf after dequeuing it.
+The address conversion of the next pointer is to prevent the chained mbuf
+in different hugepage segments from causing kernel crash.
Use Case: Egress
----------------
The DPDK TX thread dequeues the mbuf and sends it to the PMD via ``rte_eth_tx_burst()``.
It then puts the mbuf back in the cache.
+IOVA = VA: Support
+------------------
+
+KNI operates in IOVA_VA scheme when
+
+- LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0) and
+- EAL option `iova-mode=va` is passed or bus IOVA scheme in the DPDK is selected
+ as RTE_IOVA_VA.
+
+Due to IOVA to KVA address translations, based on the KNI use case there
+can be a performance impact. For mitigation, forcing IOVA to PA via EAL
+"--iova-mode=pa" option can be used, IOVA_DC bus iommu scheme can also
+result in IOVA as PA.
+
Ethtool
-------
-Ethtool is a Linux-specific tool with corresponding support in the kernel
-where each net device must register its own callbacks for the supported operations.
-The current implementation uses the igb/ixgbe modified Linux drivers for ethtool support.
-Ethtool is not supported in i40e and VMs (VF or EM devices).
+Ethtool is a Linux-specific tool with corresponding support in the kernel.
+The current version of kni provides minimal ethtool functionality
+including querying version and link state. It does not support link
+control, statistics, or dumping device registers.
git.droids-corp.org / dpdk.git / blobdiff