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.. BSD LICENSE
Copyright(c) 2015 Netronome Systems, Inc. All rights reserved.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of Intel Corporation nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
NFP poll mode driver library
============================
Netronome's sixth generation of flow processors pack 216 programmable
cores and over 100 hardware accelerators that uniquely combine packet,
flow, security and content processing in a single device that scales
up to 400 Gbps.
This document explains how to use DPDK with the Netronome Poll Mode
Driver (PMD) supporting Netronome's Network Flow Processor 6xxx
(NFP-6xxx).
Currently the driver supports virtual functions (VFs) only.
Dependencies
------------
Before using the Netronome's DPDK PMD some NFP-6xxx configuration,
which is not related to DPDK, is required. The system requires
installation of **Netronome's BSP (Board Support Package)** which includes
Linux drivers, programs and libraries.
If you have a NFP-6xxx device you should already have the code and
documentation for doing this configuration. Contact
**support@netronome.com** to obtain the latest available firmware.
The NFP Linux kernel drivers (including the required PF driver for the
NFP) are available on Github at
**https://github.com/Netronome/nfp-drv-kmods** along with build
instructions.
DPDK runs in userspace and PMDs uses the Linux kernel UIO interface to
allow access to physical devices from userspace. The NFP PMD requires
the **igb_uio** UIO driver, available with DPDK, to perform correct
initialization.
Building the software
---------------------
Netronome's PMD code is provided in the **drivers/net/nfp** directory.
Because Netronome´s BSP dependencies the driver is disabled by default
in DPDK build using **common_linuxapp configuration** file. Enabling the
driver or if you use another configuration file and want to have NFP
support, this variable is needed:
- **CONFIG_RTE_LIBRTE_NFP_PMD=y**
Once DPDK is built all the DPDK apps and examples include support for
the NFP PMD.
System configuration
--------------------
Using the NFP PMD is not different to using other PMDs. Usual steps are:
#. **Configure hugepages:** All major Linux distributions have the hugepages
functionality enabled by default. By default this allows the system uses for
working with transparent hugepages. But in this case some hugepages need to
be created/reserved for use with the DPDK through the hugetlbfs file system.
First the virtual file system need to be mounted:
.. code-block:: console
mount -t hugetlbfs none /mnt/hugetlbfs
The command uses the common mount point for this file system and it needs to
be created if necessary.
Configuring hugepages is performed via sysfs:
.. code-block:: console
/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
This sysfs file is used to specify the number of hugepages to reserve.
For example:
.. code-block:: console
echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
This will reserve 2GB of memory using 1024 2MB hugepages. The file may be
read to see if the operation was performed correctly:
.. code-block:: console
cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
The number of unused hugepages may also be inspected.
Before executing the DPDK app it should match the value of nr_hugepages.
.. code-block:: console
cat /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages
The hugepages reservation should be performed at system initialization and
it is usual to use a kernel parameter for configuration. If the reservation
is attempted on a busy system it will likely fail. Reserving memory for
hugepages may be done adding the following to the grub kernel command line:
.. code-block:: console
default_hugepagesz=1M hugepagesz=2M hugepages=1024
This will reserve 2GBytes of memory using 2Mbytes huge pages.
Finally, for a NUMA system the allocation needs to be made on the correct
NUMA node. In a DPDK app there is a master core which will (usually) perform
memory allocation. It is important that some of the hugepages are reserved
on the NUMA memory node where the network device is attached. This is because
of a restriction in DPDK by which TX and RX descriptors rings must be created
on the master code.
Per-node allocation of hugepages may be inspected and controlled using sysfs.
For example:
.. code-block:: console
cat /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
For a NUMA system there will be a specific hugepage directory per node
allowing control of hugepage reservation. A common problem may occur when
hugepages reservation is performed after the system has been working for
some time. Configuration using the global sysfs hugepage interface will
succeed but the per-node allocations may be unsatisfactory.
The number of hugepages that need to be reserved depends on how the app uses
TX and RX descriptors, and packets mbufs.
#. **Enable SR-IOV on the NFP-6xxx device:** The current NFP PMD works with
Virtual Functions (VFs) on a NFP device. Make sure that one of the Physical
Function (PF) drivers from the above Github repository is installed and
loaded.
Virtual Functions need to be enabled before they can be used with the PMD.
Before enabling the VFs it is useful to obtain information about the
current NFP PCI device detected by the system:
.. code-block:: console
lspci -d19ee:
Now, for example, configure two virtual functions on a NFP-6xxx device
whose PCI system identity is "0000:03:00.0":
.. code-block:: console
echo 2 > /sys/bus/pci/devices/0000:03:00.0/sriov_numvfs
The result of this command may be shown using lspci again:
.. code-block:: console
lspci -d19ee: -k
Two new PCI devices should appear in the output of the above command. The
-k option shows the device driver, if any, that devices are bound to.
Depending on the modules loaded at this point the new PCI devices may be
bound to nfp_netvf driver.
#. **To install the uio kernel module (manually):** All major Linux
distributions have support for this kernel module so it is straightforward
to install it:
.. code-block:: console
modprobe uio
The module should now be listed by the lsmod command.
#. **To install the igb_uio kernel module (manually):** This module is part
of DPDK sources and configured by default (CONFIG_RTE_EAL_IGB_UIO=y).
.. code-block:: console
modprobe igb_uio.ko
The module should now be listed by the lsmod command.
Depending on which NFP modules are loaded, it could be necessary to
detach NFP devices from the nfp_netvf module. If this is the case the
device needs to be unbound, for example:
.. code-block:: console
echo 0000:03:08.0 > /sys/bus/pci/devices/0000:03:08.0/driver/unbind
lspci -d19ee: -k
The output of lspci should now show that 0000:03:08.0 is not bound to
any driver.
The next step is to add the NFP PCI ID to the IGB UIO driver:
.. code-block:: console
echo 19ee 6003 > /sys/bus/pci/drivers/igb_uio/new_id
And then to bind the device to the igb_uio driver:
.. code-block:: console
echo 0000:03:08.0 > /sys/bus/pci/drivers/igb_uio/bind
lspci -d19ee: -k
lspci should show that device bound to igb_uio driver.
#. **Using scripts to install and bind modules:** DPDK provides scripts which are
useful for installing the UIO modules and for binding the right device to those
modules avoiding doing so manually:
* **dpdk-setup.sh**
* **dpdk-devbind.py**
Configuration may be performed by running dpdk-setup.sh which invokes
dpdk-devbind.py as needed. Executing dpdk-setup.sh will display a menu of
configuration options.
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