[net-2.6 PATCH v2 1/2] igb.txt: Add igb documentation

From: Jeff Kirsher
Date: Sun Aug 08 2010 - 22:00:39 EST


Add documentation for the igb networking driver.

v2:
- Removed trailing white space
- Removed Ethtool version info
- Removed LRO kernel version info

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Tested-by: Jeff Pieper <jeffrey.e.pieper@xxxxxxxxx>
---

Documentation/networking/igb.txt | 132 ++++++++++++++++++++++++++++++++++++++
1 files changed, 132 insertions(+), 0 deletions(-)
create mode 100644 Documentation/networking/igb.txt

diff --git a/Documentation/networking/igb.txt b/Documentation/networking/igb.txt
new file mode 100644
index 0000000..ab2d718
--- /dev/null
+++ b/Documentation/networking/igb.txt
@@ -0,0 +1,132 @@
+Linux* Base Driver for Intel(R) Network Connection
+==================================================
+
+Intel Gigabit Linux driver.
+Copyright(c) 1999 - 2010 Intel Corporation.
+
+Contents
+========
+
+- Identifying Your Adapter
+- Additional Configurations
+- Support
+
+Identifying Your Adapter
+========================
+
+This driver supports all 82575, 82576 and 82580-based Intel (R) gigabit network
+connections.
+
+For specific 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
+
+Command Line Parameters
+=======================
+
+The default value for each parameter is generally the recommended setting,
+unless otherwise noted.
+
+max_vfs
+-------
+Valid Range: 0-7
+Default Value: 0
+
+This parameter adds support for SR-IOV. It causes the driver to spawn up to
+max_vfs worth of virtual function.
+
+Additional Configurations
+=========================
+
+ Jumbo Frames
+ ------------
+ Jumbo Frames support is enabled by changing the MTU to a value larger than
+ the default 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.
+
+ Notes:
+
+ - 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 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.
+
+ http://sourceforge.net/projects/gkernel.
+
+ Enabling Wake on LAN* (WoL)
+ ---------------------------
+ WoL is configured through the Ethtool* utility.
+
+ For instructions on enabling WoL with Ethtool, refer to the Ethtool man page.
+
+ WoL will be enabled on the system during the next shut down or reboot.
+ For this driver version, in order to enable WoL, the igb driver must be
+ loaded when shutting down or rebooting the system.
+
+ Wake On LAN is only supported on port A of multi-port adapters.
+
+ Wake On LAN is not supported for the Intel(R) Gigabit VT Quad Port Server
+ Adapter.
+
+ Multiqueue
+ ----------
+ In this mode, a separate MSI-X vector is allocated for each queue and one
+ for "other" interrupts such as link status change and errors. All
+ interrupts are throttled via interrupt moderation. Interrupt moderation
+ must be used to avoid interrupt storms while the driver is processing one
+ interrupt. The moderation value should be at least as large as the expected
+ time for the driver to process an interrupt. Multiqueue is off by default.
+
+ REQUIREMENTS: MSI-X support is required for Multiqueue. If MSI-X is not
+ found, the system will fallback to MSI or to Legacy interrupts.
+
+ LRO
+ ---
+ Large Receive Offload (LRO) is a technique for increasing inbound throughput
+ of high-bandwidth network connections by reducing CPU overhead. It works by
+ aggregating multiple incoming packets from a single stream into a larger
+ buffer before they are passed higher up the networking stack, thus reducing
+ the number of packets that have to be processed. LRO combines multiple
+ Ethernet frames into a single receive in the stack, thereby potentially
+ decreasing CPU utilization for receives.
+
+ NOTE: You need to have inet_lro enabled via either the CONFIG_INET_LRO or
+ CONFIG_INET_LRO_MODULE kernel config option. Additionally, if
+ CONFIG_INET_LRO_MODULE is used, the inet_lro module needs to be loaded
+ before the igb driver.
+
+ You can verify that the driver is using LRO by looking at these counters in
+ Ethtool:
+
+ lro_aggregated - count of total packets that were combined
+ lro_flushed - counts the number of packets flushed out of LRO
+ lro_no_desc - counts the number of times an LRO descriptor was not available
+ for the LRO packet
+
+ NOTE: IPv6 and UDP are not supported by LRO.
+
+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@xxxxxxxxxxxx

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