X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fsample_app_ug%2Fkernel_nic_interface.rst;h=aac4ebd8d4ffe0ef96076478edf02ecd8fca48a9;hb=0b133c36ad7d5fdce852b060d69019d69d48a7cb;hp=1b3ee9a5ebd52895eae6072755bf945d8016ce03;hpb=05096a8be5d2eac6eed6dba926259b97c3fffebd;p=dpdk.git diff --git a/doc/guides/sample_app_ug/kernel_nic_interface.rst b/doc/guides/sample_app_ug/kernel_nic_interface.rst index 1b3ee9a5eb..aac4ebd8d4 100644 --- a/doc/guides/sample_app_ug/kernel_nic_interface.rst +++ b/doc/guides/sample_app_ug/kernel_nic_interface.rst @@ -21,28 +21,37 @@ The FIFO queues contain pointers to data packets in the DPDK. This: * Provides a faster mechanism to interface with the kernel net stack and eliminates system calls -* Facilitates the DPDK using standard Linux* userspace net tools (tcpdump, ftp, and so on) +* Facilitates the DPDK using standard Linux* userspace net tools (tshark, rsync, and so on) * Eliminate the copy_to_user and copy_from_user operations on packets. The Kernel NIC Interface sample application is a simple example that demonstrates the use of the DPDK to create a path for packets to go through the Linux* kernel. This is done by creating one or more kernel net devices for each of the DPDK ports. -The application allows the use of standard Linux tools (ethtool, ifconfig, tcpdump) with the DPDK ports and +The application allows the use of standard Linux tools (ethtool, iproute, tshark) with the DPDK ports and also the exchange of packets between the DPDK application and the Linux* kernel. +The Kernel NIC Interface sample application requires that the +KNI kernel module ``rte_kni`` be loaded into the kernel. See +:doc:`../prog_guide/kernel_nic_interface` for more information on loading +the ``rte_kni`` kernel module. + Overview -------- -The Kernel NIC Interface sample application uses two threads in user space for each physical NIC port being used, -and allocates one or more KNI device for each physical NIC port with kernel module's support. -For a physical NIC port, one thread reads from the port and writes to KNI devices, -and another thread reads from KNI devices and writes the data unmodified to the physical NIC port. -It is recommended to configure one KNI device for each physical NIC port. -If configured with more than one KNI devices for a physical NIC port, -it is just for performance testing, or it can work together with VMDq support in future. +The Kernel NIC Interface sample application ``kni`` allocates one or more +KNI interfaces for each physical NIC port. For each physical NIC port, +``kni`` uses two DPDK threads in user space; one thread reads from the port and +writes to the corresponding KNI interfaces and the other thread reads from +the KNI interfaces and writes the data unmodified to the physical NIC port. + +It is recommended to configure one KNI interface for each physical NIC port. +The application can be configured with more than one KNI interface for +each physical NIC port for performance testing or it can work together with +VMDq support in future. -The packet flow through the Kernel NIC Interface application is as shown in the following figure. +The packet flow through the Kernel NIC Interface application is as shown +in the following figure. .. _figure_kernel_nic: @@ -50,145 +59,217 @@ The packet flow through the Kernel NIC Interface application is as shown in the Kernel NIC Application Packet Flow +If link monitoring is enabled with the ``-m`` command line flag, one +additional pthread is launched which will check the link status of each +physical NIC port and will update the carrier status of the corresponding +KNI interface(s) to match the physical NIC port's state. This means that +the KNI interface(s) will be disabled automatically when the Ethernet link +goes down and enabled when the Ethernet link goes up. + +If link monitoring is enabled, the ``rte_kni`` kernel module should be loaded +such that the :ref:`default carrier state ` is +set to *off*. This ensures that the KNI interface is only enabled *after* +the Ethernet link of the corresponding NIC port has reached the linkup state. + +If link monitoring is not enabled, the ``rte_kni`` kernel module should be +loaded with the :ref:`default carrier state ` +set to *on*. This sets the carrier state of the KNI interfaces to *on* +when the KNI interfaces are enabled without regard to the actual link state +of the corresponding NIC port. This is useful for testing in loopback +mode where the NIC port may not be physically connected to anything. + Compiling the Application ------------------------- To compile the sample application see :doc:`compiling`. -The application is located in the ``kni`` sub-directory. +The application is located in the ``examples/kni`` sub-directory. .. note:: - This application is intended as a linuxapp only. + This application is intended as a linux only. -Loading the Kernel Module -------------------------- +Running the kni Example Application +----------------------------------- -Loading the KNI kernel module without any parameter is the typical way a DPDK application -gets packets into and out of the kernel net stack. -This way, only one kernel thread is created for all KNI devices for packet receiving in kernel side: +The ``kni`` example application requires a number of command line options: .. code-block:: console - #insmod rte_kni.ko + kni [EAL options] -- -p PORTMASK --config="(port,lcore_rx,lcore_tx[,lcore_kthread,...])[,(port,lcore_rx,lcore_tx[,lcore_kthread,...])]" [-P] [-m] -Pinning the kernel thread to a specific core can be done using a taskset command such as following: +Where: -.. code-block:: console +* ``-p PORTMASK``: - #taskset -p 100000 `pgrep --fl kni_thread | awk '{print $1}'` + Hexadecimal bitmask of ports to configure. -This command line tries to pin the specific kni_thread on the 20th lcore (lcore numbering starts at 0), -which means it needs to check if that lcore is available on the board. -This command must be sent after the application has been launched, as insmod does not start the kni thread. +* ``--config="(port,lcore_rx,lcore_tx[,lcore_kthread,...])[,(port,lcore_rx,lcore_tx[,lcore_kthread,...])]"``: -For optimum performance, -the lcore in the mask must be selected to be on the same socket as the lcores used in the KNI application. + Determines which lcores the Rx and Tx DPDK tasks, and (optionally) + the KNI kernel thread(s) are bound to for each physical port. -To provide flexibility of performance, the kernel module of the KNI, -located in the kmod sub-directory of the DPDK target directory, -can be loaded with parameter of kthread_mode as follows: +* ``-P``: -* #insmod rte_kni.ko kthread_mode=single + Optional flag to set all ports to promiscuous mode so that packets are + accepted regardless of the packet's Ethernet MAC destination address. + Without this option, only packets with the Ethernet MAC destination + address set to the Ethernet address of the port are accepted. - This mode will create only one kernel thread for all KNI devices for packet receiving in kernel side. - By default, it is in this single kernel thread mode. - It can set core affinity for this kernel thread by using Linux command taskset. +* ``-m``: -* #insmod rte_kni.ko kthread_mode =multiple + Optional flag to enable monitoring and updating of the Ethernet + carrier state. With this option set, a thread will be started which + will periodically check the Ethernet link status of the physical + Ethernet ports and set the carrier state of the corresponding KNI + network interface to match it. This means that the KNI interface will + be disabled automatically when the Ethernet link goes down and enabled + when the Ethernet link goes up. - This mode will create a kernel thread for each KNI device for packet receiving in kernel side. - The core affinity of each kernel thread is set when creating the KNI device. - The lcore ID for each kernel thread is provided in the command line of launching the application. - Multiple kernel thread mode can provide scalable higher performance. +Refer to *DPDK Getting Started Guide* for general information on running +applications and the Environment Abstraction Layer (EAL) options. -To measure the throughput in a loopback mode, the kernel module of the KNI, -located in the kmod sub-directory of the DPDK target directory, -can be loaded with parameters as follows: +The ``-c coremask`` or ``-l corelist`` parameter of the EAL options must +include the lcores specified by ``lcore_rx`` and ``lcore_tx`` for each port, +but does not need to include lcores specified by ``lcore_kthread`` as those +cores are used to pin the kernel threads in the ``rte_kni`` kernel module. -* #insmod rte_kni.ko lo_mode=lo_mode_fifo +The ``--config`` parameter must include a set of +``(port,lcore_rx,lcore_tx,[lcore_kthread,...])`` values for each physical +port specified in the ``-p PORTMASK`` parameter. - This loopback mode will involve ring enqueue/dequeue operations in kernel space. +The optional ``lcore_kthread`` lcore ID parameter in ``--config`` can be +specified zero, one or more times for each physical port. -* #insmod rte_kni.ko lo_mode=lo_mode_fifo_skb +If no lcore ID is specified for ``lcore_kthread``, one KNI interface will +be created for the physical port ``port`` and the KNI kernel thread(s) +will have no specific core affinity. - This loopback mode will involve ring enqueue/dequeue operations and sk buffer copies in kernel space. +If one or more lcore IDs are specified for ``lcore_kthread``, a KNI interface +will be created for each lcore ID specified, bound to the physical port +``port``. If the ``rte_kni`` kernel module is loaded in :ref:`multiple +kernel thread ` mode, a kernel thread will be created +for each KNI interface and bound to the specified core. If the ``rte_kni`` +kernel module is loaded in :ref:`single kernel thread ` +mode, only one kernel thread is started for all KNI interfaces. The kernel +thread will be bound to the first ``lcore_kthread`` lcore ID specified. -Running the Application ------------------------ +Example Configurations +~~~~~~~~~~~~~~~~~~~~~~~ -The application requires a number of command line options: +The following commands will first load the ``rte_kni`` kernel module in +:ref:`multiple kernel thread ` mode. The ``kni`` +application is then started using two ports; Port 0 uses lcore 4 for the +Rx task, lcore 6 for the Tx task, and will create a single KNI interface +``vEth0_0`` with the kernel thread bound to lcore 8. Port 1 uses lcore +5 for the Rx task, lcore 7 for the Tx task, and will create a single KNI +interface ``vEth1_0`` with the kernel thread bound to lcore 9. .. code-block:: console - kni [EAL options] -- -P -p PORTMASK --config="(port,lcore_rx,lcore_tx[,lcore_kthread,...])[,port,lcore_rx,lcore_tx[,lcore_kthread,...]]" + # rmmod rte_kni + # insmod kmod/rte_kni.ko kthread_mode=multiple + # ./build/kni -l 4-7 -n 4 -- -P -p 0x3 -m --config="(0,4,6,8),(1,5,7,9)" -Where: +The following example is identical, except an additional ``lcore_kthread`` +core is specified per physical port. In this case, ``kni`` will create +four KNI interfaces: ``vEth0_0``/``vEth0_1`` bound to physical port 0 and +``vEth1_0``/``vEth1_1`` bound to physical port 1. -* -P: Set all ports to promiscuous mode so that packets are accepted regardless of the packet's Ethernet MAC destination address. - Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted. +The kernel thread for each interface will be bound as follows: -* -p PORTMASK: Hexadecimal bitmask of ports to configure. + * ``vEth0_0`` - bound to lcore 8. + * ``vEth0_1`` - bound to lcore 10. + * ``vEth1_0`` - bound to lcore 9. + * ``vEth1_1`` - bound to lcore 11 -* --config="(port,lcore_rx, lcore_tx[,lcore_kthread, ...]) [, port,lcore_rx, lcore_tx[,lcore_kthread, ...]]": - Determines which lcores of RX, TX, kernel thread are mapped to which ports. - -Refer to *DPDK Getting Started Guide* for general information on running applications and the Environment Abstraction Layer (EAL) options. +.. code-block:: console -The -c coremask or -l corelist parameter of the EAL options should include the lcores indicated by the lcore_rx and lcore_tx, -but does not need to include lcores indicated by lcore_kthread as they are used to pin the kernel thread on. -The -p PORTMASK parameter should include the ports indicated by the port in --config, neither more nor less. + # rmmod rte_kni + # insmod kmod/rte_kni.ko kthread_mode=multiple + # ./build/kni -l 4-7 -n 4 -- -P -p 0x3 -m --config="(0,4,6,8,10),(1,5,7,9,11)" -The lcore_kthread in --config can be configured none, one or more lcore IDs. -In multiple kernel thread mode, if configured none, a KNI device will be allocated for each port, -while no specific lcore affinity will be set for its kernel thread. -If configured one or more lcore IDs, one or more KNI devices will be allocated for each port, -while specific lcore affinity will be set for its kernel thread. -In single kernel thread mode, if configured none, a KNI device will be allocated for each port. -If configured one or more lcore IDs, -one or more KNI devices will be allocated for each port while -no lcore affinity will be set as there is only one kernel thread for all KNI devices. +The following example can be used to test the interface between the ``kni`` +test application and the ``rte_kni`` kernel module. In this example, +the ``rte_kni`` kernel module is loaded in :ref:`single kernel thread +mode `, :ref:`loopback mode ` +enabled, and the :ref:`default carrier state ` +is set to *on* so that the corresponding physical NIC port does not have +to be connected in order to use the KNI interface. One KNI interface +``vEth0_0`` is created for port 0 and one KNI interface ``vEth1_0`` is +created for port 1. Since ``rte_kni`` is loaded in "single kernel thread" +mode, the one kernel thread is bound to lcore 8. -For example, to run the application with two ports served by six lcores, one lcore of RX, one lcore of TX, -and one lcore of kernel thread for each port: +Since the physical NIC ports are not being used, link monitoring can be +disabled by **not** specifying the ``-m`` flag to ``kni``: .. code-block:: console - ./build/kni -l 4-7 -n 4 -- -P -p 0x3 --config="(0,4,6,8),(1,5,7,9)" + # rmmod rte_kni + # insmod kmod/rte_kni.ko lo_mode=lo_mode_fifo carrier=on + # ./build/kni -l 4-7 -n 4 -- -P -p 0x3 --config="(0,4,6,8),(1,5,7,9)" KNI Operations -------------- -Once the KNI application is started, one can use different Linux* commands to manage the net interfaces. -If more than one KNI devices configured for a physical port, -only the first KNI device will be paired to the physical device. -Operations on other KNI devices will not affect the physical port handled in user space application. +Once the ``kni`` application is started, the user can use the normal +Linux commands to manage the KNI interfaces as if they were any other +Linux network interface. + +Enable KNI interface and assign an IP address: + +.. code-block:: console + + # ip addr add dev vEth0_0 192.168.0.1 -Assigning an IP address: +Show KNI interface configuration and statistics: .. code-block:: console - #ifconfig vEth0_0 192.168.0.1 + # ip -s -d addr show vEth0_0 -Displaying the NIC registers: +The user can also check and reset the packet statistics inside the ``kni`` +application by sending the app the USR1 and USR2 signals: .. code-block:: console - #ethtool -d vEth0_0 + # Print statistics + # pkill -USR1 kni -Dumping the network traffic: + # Zero statistics + # pkill -USR2 kni + +Dump network traffic: .. code-block:: console - #tcpdump -i vEth0_0 + # tshark -n -i vEth0_0 + +The normal Linux commands can also be used to change the MAC address and +MTU size used by the physical NIC which corresponds to the KNI interface. +However, if more than one KNI interface is configured for a physical port, +these commands will only work on the first KNI interface for that port. Change the MAC address: .. code-block:: console - #ifconfig vEth0_0 hw ether 0C:01:02:03:04:08 + # ip link set dev vEth0_0 lladdr 0C:01:02:03:04:08 -When the DPDK userspace application is closed, all the KNI devices are deleted from Linux*. +Change the MTU size: + +.. code-block:: console + + # ip link set dev vEth0_0 mtu 1450 + +Limited ethtool support: + +.. code-block:: console + + # ethtool -i vEth0_0 + +When the ``kni`` application is closed, all the KNI interfaces are deleted +from the Linux kernel. Explanation ----------- @@ -227,7 +308,7 @@ to see if this lcore is reading from or writing to kernel NIC interfaces. For the case that reads from a NIC port and writes to the kernel NIC interfaces (``kni_ingress``), the packet reception is the same as in L2 Forwarding sample application (see :ref:`l2_fwd_app_rx_tx_packets`). -The packet transmission is done by sending mbufs into the kernel NIC interfaces by rte_kni_tx_burst(). +The packet transmission is done by sending mbufs into the kernel NIC interfaces by ``rte_kni_tx_burst()``. The KNI library automatically frees the mbufs after the kernel successfully copied the mbufs. For the other case that reads from kernel NIC interfaces @@ -235,16 +316,3 @@ and writes to a physical NIC port (``kni_egress``), packets are retrieved by reading mbufs from kernel NIC interfaces by ``rte_kni_rx_burst()``. The packet transmission is the same as in the L2 Forwarding sample application (see :ref:`l2_fwd_app_rx_tx_packets`). - -Callbacks for Kernel Requests -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -To execute specific PMD operations in user space requested by some Linux* commands, -callbacks must be implemented and filled in the struct rte_kni_ops structure. -Currently, setting a new MTU, change in MAC address, configuring promiscusous mode and -configuring the network interface(up/down) re supported. -Default implementation for following is available in rte_kni library. -Application may choose to not implement following callbacks: - -- ``config_mac_address`` -- ``config_promiscusity``