

igbvf Linux* Base Driver for Intel Ethernet Network Connection
===============================================================


================================================================================

March 31, 2015

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- Overview
- Identifying Your Adapter
- Building and Installation
- Command Line Parameters
- Additional Configurations
- Known Issues
- Support
- License

================================================================================


Overview
--------


This file describes the igbvf Linux* Base Driver for Intel Ethernet Network
Connections. This driver supports upstream kernel versions 2.6.30 (or newer)
x86_64.

Supported Operating Systems include:

- RHEL 6.6
- SLES 11 SP3 x86_64

The igbvf driver supports 82576-based virtual function devices that can only
be activated on kernels that support SR-IOV. SR-IOV requires the correct
platform and OS support.

The igbvf driver requires the igb driver, version 2.0 or later. The igbvf
driver supports virtual functions generated by the igb driver with a max_vfs
value of 1 or greater. For more information on the max_vfs parameter refer to
the readme file included with the igb driver.

The guest OS loading the igbvf driver must support MSI-X interrupts.

This driver is only supported as a loadable module at this time. Intel is not
supplying patches against the kernel source to allow for static linking of the
driver. For questions related to hardware requirements, refer to the
documentation supplied with your Intel Ethernet Gigabit adapter. All hardware
requirements listed apply to use with Linux.

Instructions on updating ethtool can be found in the section "Additional
Configurations" later in this document.

VLANs: There is a limit of a total of 32 shared VLANs to 1 or more VFs.

================================================================================


Identifying Your Adapter
------------------------


For more information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:
http://support.intel.com/support/go/network/adapter/idguide.htm

For the latest Intel network drivers for Linux, refer to the following
website. Select the link for your adapter.
http://support.intel.com/support/go/network/adapter/home.htm
================================================================================


Building and Installation
-------------------------


To build a binary RPM* package of this driver, run 'rpmbuild -tb
<filename.tar.gz>'. Replace <filename.tar.gz> with the specific filename of
the driver.

NOTES:

- For the build to work properly, the currently running kernel MUST match
  the version and configuration of the installed kernel sources. If you have
  just recompiled the kernel reboot the system now.
- RPM functionality has only been tested in Red Hat distributions.

1. Move the base driver tar file to the directory of your choice. For
   example, use '/home/username/igbvf' or '/usr/local/src/igbvf'.

2. Untar/unzip the archive, where <x.x.x> is the version number for the
   driver tar file:
   tar zxf igbvf-<x.x.x>.tar.gz
3. Change to the driver src directory, where <x.x.x> is the version number
   for the driver tar:
   cd igbvf-<x.x.x>/src/
4. Compile the driver module:
   # make install

   The binary will be installed as:
   /lib/modules/<KERNEL VERSION>/kernel/drivers/net/igbvf/igbvf.[k]o

   The install location listed above is the default location. This may differ
   for various Linux distributions.

5. Load the module using the modprobe command:
   modprobe igbvf

   With 2.6 based kernels also make sure that older igbvf drivers are removed
   from the kernel, before loading the new module:
   rmmod igbvf; modprobe igbvf
6. Assign an IP address to the interface by entering the following, where x
   is the interface number:
   ifconfig eth <x> <IP_address>
7. Verify that the interface works. Enter the following, where IP_address
   is the IP address for another machine on the same subnet as the interface
   that is being tested:
   ping <IP_address>

TROUBLESHOOTING: Some systems have trouble supporting MSI and/or MSI-X
interrupts. If you believe your system needs to disable this style of
interrupt, the driver can be built and installed with the command:
# make CFLAGS_EXTRA=-DDISABLE_PCI_MSI install

Normally the driver will generate an interrupt every two seconds, so if you
can see that you are no longer getting interrupts in cat /proc/interrupts for
the ethX igbvf device, then this workaround may be necessary.

================================================================================


Command Line Parameters
-----------------------


If the driver is built as a module, the following optional parameters are used
by entering them on the command line with the modprobe command using this
syntax:
modprobe igbvf [<option>=<VAL1>,<VAL2>,...]

There needs to be a <VAL#> for each network port in the system supported by
this driver. The values will be applied to each instance, in function order.
For example:
modprobe igbvf InterruptThrottleRate=16000,16000

In this case, there are two network ports supported by igbvf in the system.
The default value for each parameter is generally the recommended setting,
unless otherwise noted.

NOTES:

- For more information about the InterruptThrottleRate parameter, see the
  application note at: http://www.intel.com/design/network/applnots/ap450.htm
- A descriptor describes a data buffer and attributes related to the data
  buffer. This information is accessed by the hardware.


InterruptThrottleRate
---------------------


Valid Range:  0,1,3, 100-100000 (0=off, 1=dynamic, 3=dynamic conservative)

Default Value:  3

The driver can limit the amount of interrupts per second that the adapter will
generate for incoming packets. It does this by writing a value to the adapter
that is based on the maximum amount of interrupts that the adapter will
generate per second.

Setting InterruptThrottleRate to a value greater or equal to 100 will program
the adapter to send out a maximum of that many interrupts per second, even if
more packets have come in. This reduces interrupt load on the system and can
lower CPU utilization under heavy load, but will increase latency as packets
are not processed as quickly.

The default behavior of the driver previously assumed a static
InterruptThrottleRate value of 8000, providing a good fallback value for all
traffic types, but lacking in small packet performance and latency. However,
the hardware can handle many more small packets per second. For this reason,
an adaptive interrupt moderation algorithm was implemented.

The driver has two adaptive modes (setting 1 or 3) in which it dynamically
adjusts the InterruptThrottleRate value based on the traffic that it receives.
After determining the type of incoming traffic in the last timeframe, it will
adjust the InterruptThrottleRate to an appropriate value for that traffic.

The algorithm classifies the incoming traffic every interval into classes.
Once the class is determined, the InterruptThrottleRate value is adjusted to
suit that traffic type the best. There are three classes defined:

- "Bulk traffic", for large amounts of packets of normal size
- "Low latency", for small amounts of traffic and/or a significant
  percentage of small packets
- "Lowest latency", for almost completely small packets or minimal traffic

In dynamic conservative mode, the InterruptThrottleRate value is set to 4000
for traffic that falls in class "Bulk traffic". If traffic falls in the "Low
latency" or "Lowest latency" class, the InterruptThrottleRate is increased
stepwise to 20000. This default mode is suitable for most applications.

For situations where low latency is vital, such as cluster or grid computing,
the algorithm can reduce latency even more when InterruptThrottleRate is set
to mode 1. In this mode, which operates the same as mode 3, the
InterruptThrottleRate will be increased stepwise to 70000 for traffic in class
"Lowest latency".

Setting InterruptThrottleRate to 0 turns off any interrupt moderation and may
improve small packet latency, but is generally not suitable for bulk
throughput traffic.

NOTES:

- Dynamic interrupt throttling is only applicable to adapters operating in
  MSI or Legacy interrupt mode, using a single receive queue.
- When igbvf is loaded with default settings and multiple adapters are in
  use simultaneously, the CPU utilization may increase non-linearly. In order
  to limit the CPU utilization without impacting the overall throughput, we
  recommend that you load the driver as follows: modprobe igbvf
  InterruptThrottleRate=3000,3000,3000 This sets the InterruptThrottleRate to
  3000 interrupts/sec for the first, second, and third instances of the
  driver. The range of 2000 to 3000 interrupts per second works on a majority
  of systems and is a good starting point, but the optimal value will be
  platform-specific. If CPU utilization is not a concern, use default driver
  settings.

================================================================================


Additional Configurations
-------------------------



Configuring the Driver on Different Distributions
-------------------------------------------------


Configuring a network driver to load properly when the system is started is
distribution dependent. Typically, the configuration process involves adding
an alias line to /etc/modules.conf or /etc/modprobe.conf as well as editing
other system startup scripts and/or configuration files. Many popular Linux
distributions ship with tools to make these changes for you. To learn the
proper way to configure a network device for your system, refer to your
distribution documentation. If during this process you are asked for the
driver or module name, the name for the Linux Base Driver for the Gigabit
Family of Adapters is igbvf.

As an example, if you install the igbvf driver for two adapters (eth0 and
eth1) and want to set the interrupt mode to MSI-X and MSI respectively, add
the following to modules.conf or /etc/modprobe.conf:
alias eth0 igbvf
alias eth1 igbvf
options igbvf InterruptThrottleRate=3,1

Viewing Link Messages
---------------------


Link messages will not be displayed to the console if the distribution is
restricting system messages. In order to see network driver link messages on
your console, set dmesg to eight by entering the following: dmesg -n 8

NOTES: This setting is not saved across reboots.


Jumbo Frames
------------


Jumbo Frames support is enabled by changing the Maximum Transmission Unit
(MTU) to a value larger than the default value of 1500. Use the ifconfig
command to increase the MTU size. For example:
ifconfig eth<x> mtu 9000 up

This setting is not saved across reboots. The setting change can be made
permanent by adding MTU=9000

to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>. This example applies
to the Red Hat distributions. Other distributions may store this setting in a
different location.

NOTES:

- To enable Jumbo Frames, increase the MTU size on the interface beyond 1500.
- The maximum MTU setting for Jumbo Frames is 9216. This value coincides
  with the maximum Jumbo Frames size of 9234 bytes.
- Using Jumbo frames at 10 or 100 Mbps is not supported and may result in
  poor performance or loss of link.


ethtool
-------


The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. ethtool version 3
or later is required for this functionality, although we strongly recommend
downloading the latest version at:
http://ftp.kernel.org/pub/software/network/ethtool/.
================================================================================


Known Issues/Troubleshooting
----------------------------



Hardware Issues
---------------


For known hardware and troubleshooting issues, either refer to the "Release
Notes" in your User Guide, or for more detailed information, go to
http://www.intel.com.

In the search box enter your devices controller ID followed by "spec update"
(i.e., 82599 spec update). The specification update file has complete
information on known hardware issues.


Software Issues
---------------


NOTE: After installing the driver, if your Intel Ethernet Network Connection
is not working, verify that you have installed the correct driver.


Compiling the Driver
--------------------


When trying to compile the driver by running make install, the following error
may occur:  "Linux kernel source not configured - missing version.h"

To solve this issue, create the version.h file by going to the Linux source
tree and entering:
# make include/linux/version.h

Multiple Interfaces on Same Ethernet Broadcast Network
------------------------------------------------------


Due to the default ARP behavior on Linux, it is not possible to have one
system on two IP networks in the same Ethernet broadcast domain
(non-partitioned switch) behave as expected. All Ethernet interfaces will
respond to IP traffic for any IP address assigned to the system. This results
in unbalanced receive traffic.

If you have multiple interfaces in a server, either turn on ARP filtering by
entering: echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

This only works if your kernel's version is higher than 2.4.5.

NOTE: This setting is not saved across reboots. The configuration change can
be made permanent by adding the following line to the /etc/sysctl.conf file:
net.ipv4.conf.all.arp_filter = 1

or,
install the interfaces in separate broadcast domains (either in different
switches or in a switch partitioned to VLANs)

Do Not Use LRO When Routing Packets
-----------------------------------


Due to a known general compatibilty issue with LRO and routing, do not use LRO
when routing packets.


Build Error with Asianux 3.0 - Redefinition of typedef 'irq_handler_t'
----------------------------------------------------------------------


Some systems may experience build issues due to the redefinition of
irq_handler_t. To resolve this issue, build the driver (step 4 above) using
the command:
# make CFLAGS_EXTRA=-DAX_RELEASE_CODE=1 install

MSI-X Issues with Kernels between 2.6.19 and 2.6.21 (inclusive)
---------------------------------------------------------------


Kernel panics and instability may be observed on any MSI-X hardware if you use
irqbalance with kernels between 2.6.19 and 2.6.21. If such problems are
encountered, you may disable the irqbalance daemon or upgrade to a newer
kernel.


Rx Page Allocation Errors
-------------------------


"order:0" errors may occur under stress with kernels 2.6.25 and newer. This is
caused by the way the Linux kernel reports this stressed condition.


Under Redhat 5.4-GA, System May Crash when Closing Guest OS Window after
Loading/Unloading Physical Function (PF) Driver


Do not remove the igbvf driver from Dom0 while Virtual Functions (VFs) are
assigned to guests. VFs must first use the xm "pci-detach" command to hot-plug
the VF device out of the VM it is assigned to or else shut down the VM.


Unloading Physical Function (PF) Driver Causes System Reboots When VM is
Running and VF is Loaded on the VM


Do not unload the PF driver (igb) while VFs are assigned to guests.


Host May Reboot after Removing PF when VF is Active in Guest
------------------------------------------------------------


Using kernel versions earlier than 3.2, do not unload the PF driver with
active VFs. Doing this will cause your VFs to stop working until you reload
the PF driver and may cause a spontaneous reboot of your system.

================================================================================


Support
-------


For general information, go to the Intel support website at:
www.intel.com/support/

or the Intel Wired Networking project hosted by Sourceforge at:
http://sourceforge.net/projects/e1000

If an issue is identified with the released source code on the supported
kernel with a supported adapter, email the specific information related to the
issue to e1000-devel@lists.sf.net.

================================================================================


License
-------


Intel Gigabit Linux driver.
Copyright(c) 1999 - 2015 Intel Corporation.

This program is free software; you can redistribute it and/or modify it under
the terms and conditions of the GNU General Public License, version 2, as
published by the Free Software Foundation.

This program is distributed in the hope it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
St - Fifth Floor, Boston, MA 02110-1301 USA.

The full GNU General Public License is included in this distribution in the
file called "COPYING".

================================================================================


Trademarks
----------


Intel, Itanium, and Pentium are trademarks or registered trademarks of Intel
Corporation or its subsidiaries in the United States and other countries.

* Other names and brands may be claimed as the property of others.

