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Based on kernel version 3.16. Page generated on 2014-08-06 21:40 EST.

1	Linux Base Driver for 10 Gigabit Intel(R) Ethernet Network Connection
2	=====================================================================
3	
4	March 14, 2011
5	
6	
7	Contents
8	========
9	
10	- In This Release
11	- Identifying Your Adapter
12	- Building and Installation
13	- Command Line Parameters
14	- Improving Performance
15	- Additional Configurations
16	- Known Issues/Troubleshooting
17	- Support
18	
19	
20	
21	In This Release
22	===============
23	
24	This file describes the ixgb Linux Base Driver for the 10 Gigabit Intel(R)
25	Network Connection.  This driver includes support for Itanium(R)2-based
26	systems.
27	
28	For questions related to hardware requirements, refer to the documentation
29	supplied with your 10 Gigabit adapter.  All hardware requirements listed apply
30	to use with Linux.
31	
32	The following features are available in this kernel:
33	 - Native VLANs
34	 - Channel Bonding (teaming)
35	 - SNMP
36	
37	Channel Bonding documentation can be found in the Linux kernel source:
38	/Documentation/networking/bonding.txt
39	
40	The driver information previously displayed in the /proc filesystem is not
41	supported in this release.  Alternatively, you can use ethtool (version 1.6
42	or later), lspci, and ifconfig to obtain the same information.
43	
44	Instructions on updating ethtool can be found in the section "Additional
45	Configurations" later in this document.
46	
47	
48	Identifying Your Adapter
49	========================
50	
51	The following Intel network adapters are compatible with the drivers in this
52	release:
53	
54	Controller  Adapter Name                 Physical Layer
55	----------  ------------                 --------------
56	82597EX     Intel(R) PRO/10GbE LR/SR/CX4 10G Base-LR (1310 nm optical fiber)
57	            Server Adapters              10G Base-SR (850 nm optical fiber)
58	                                         10G Base-CX4(twin-axial copper cabling)
59	
60	For more information on how to identify your adapter, go to the Adapter &
61	Driver ID Guide at:
62	
63	    http://support.intel.com/support/network/sb/CS-012904.htm
64	
65	
66	Building and Installation
67	=========================
68	
69	select m for "Intel(R) PRO/10GbE support" located at:
70	      Location:
71	        -> Device Drivers
72	          -> Network device support (NETDEVICES [=y])
73	            -> Ethernet (10000 Mbit) (NETDEV_10000 [=y])
74	1. make modules && make modules_install
75	
76	2. Load the module:
77	
78	    modprobe ixgb <parameter>=<value>
79	
80	   The insmod command can be used if the full
81	   path to the driver module is specified.  For example:
82	
83	     insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/ixgb/ixgb.ko
84	
85	   With 2.6 based kernels also make sure that older ixgb drivers are
86	   removed from the kernel, before loading the new module:
87	
88	     rmmod ixgb; modprobe ixgb
89	
90	3. Assign an IP address to the interface by entering the following, where
91	   x is the interface number:
92	
93	     ifconfig ethx <IP_address>
94	
95	4. Verify that the interface works. Enter the following, where <IP_address>
96	   is the IP address for another machine on the same subnet as the interface
97	   that is being tested:
98	
99	     ping  <IP_address>
100	
101	
102	Command Line Parameters
103	=======================
104	
105	If the driver is built as a module, the  following optional parameters are
106	used by entering them on the command line with the modprobe command using
107	this syntax:
108	
109	     modprobe ixgb [<option>=<VAL1>,<VAL2>,...]
110	
111	For example, with two 10GbE PCI adapters, entering:
112	
113	     modprobe ixgb TxDescriptors=80,128
114	
115	loads the ixgb driver with 80 TX resources for the first adapter and 128 TX
116	resources for the second adapter.
117	
118	The default value for each parameter is generally the recommended setting,
119	unless otherwise noted.
120	
121	FlowControl
122	Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)
123	Default: Read from the EEPROM
124	         If EEPROM is not detected, default is 1
125	    This parameter controls the automatic generation(Tx) and response(Rx) to
126	    Ethernet PAUSE frames.  There are hardware bugs associated with enabling
127	    Tx flow control so beware.
128	
129	RxDescriptors
130	Valid Range: 64-512
131	Default Value: 512
132	    This value is the number of receive descriptors allocated by the driver.
133	    Increasing this value allows the driver to buffer more incoming packets.
134	    Each descriptor is 16 bytes.  A receive buffer is also allocated for
135	    each descriptor and can be either 2048, 4056, 8192, or 16384 bytes,
136	    depending on the MTU setting.  When the MTU size is 1500 or less, the
137	    receive buffer size is 2048 bytes. When the MTU is greater than 1500 the
138	    receive buffer size will be either 4056, 8192, or 16384 bytes.  The
139	    maximum MTU size is 16114.
140	
141	RxIntDelay
142	Valid Range: 0-65535 (0=off)
143	Default Value: 72
144	    This value delays the generation of receive interrupts in units of
145	    0.8192 microseconds.  Receive interrupt reduction can improve CPU
146	    efficiency if properly tuned for specific network traffic.  Increasing
147	    this value adds extra latency to frame reception and can end up
148	    decreasing the throughput of TCP traffic.  If the system is reporting
149	    dropped receives, this value may be set too high, causing the driver to
150	    run out of available receive descriptors.
151	
152	TxDescriptors
153	Valid Range: 64-4096
154	Default Value: 256
155	    This value is the number of transmit descriptors allocated by the driver.
156	    Increasing this value allows the driver to queue more transmits.  Each
157	    descriptor is 16 bytes.
158	
159	XsumRX
160	Valid Range: 0-1
161	Default Value: 1
162	    A value of '1' indicates that the driver should enable IP checksum
163	    offload for received packets (both UDP and TCP) to the adapter hardware.
164	
165	
166	Improving Performance
167	=====================
168	
169	With the 10 Gigabit server adapters, the default Linux configuration will
170	very likely limit the total available throughput artificially.  There is a set
171	of configuration changes that, when applied together, will increase the ability
172	of Linux to transmit and receive data.  The following enhancements were
173	originally acquired from settings published at http://www.spec.org/web99/ for
174	various submitted results using Linux.
175	
176	NOTE: These changes are only suggestions, and serve as a starting point for
177	      tuning your network performance.
178	
179	The changes are made in three major ways, listed in order of greatest effect:
180	- Use ifconfig to modify the mtu (maximum transmission unit) and the txqueuelen
181	  parameter.
182	- Use sysctl to modify /proc parameters (essentially kernel tuning)
183	- Use setpci to modify the MMRBC field in PCI-X configuration space to increase
184	  transmit burst lengths on the bus.
185	
186	NOTE: setpci modifies the adapter's configuration registers to allow it to read
187	up to 4k bytes at a time (for transmits).  However, for some systems the
188	behavior after modifying this register may be undefined (possibly errors of
189	some kind).  A power-cycle, hard reset or explicitly setting the e6 register
190	back to 22 (setpci -d 8086:1a48 e6.b=22) may be required to get back to a
191	stable configuration.
192	
193	- COPY these lines and paste them into ixgb_perf.sh:
194	#!/bin/bash
195	echo "configuring network performance , edit this file to change the interface
196	or device ID of 10GbE card"
197	# set mmrbc to 4k reads, modify only Intel 10GbE device IDs
198	# replace 1a48 with appropriate 10GbE device's ID installed on the system,
199	# if needed.
200	setpci -d 8086:1a48 e6.b=2e
201	# set the MTU (max transmission unit) - it requires your switch and clients
202	# to change as well.
203	# set the txqueuelen
204	# your ixgb adapter should be loaded as eth1 for this to work, change if needed
205	ifconfig eth1 mtu 9000 txqueuelen 1000 up
206	# call the sysctl utility to modify /proc/sys entries
207	sysctl -p ./sysctl_ixgb.conf
208	- END ixgb_perf.sh
209	
210	- COPY these lines and paste them into sysctl_ixgb.conf:
211	# some of the defaults may be different for your kernel
212	# call this file with sysctl -p <this file>
213	# these are just suggested values that worked well to increase throughput in
214	# several network benchmark tests, your mileage may vary
215	
216	### IPV4 specific settings
217	# turn TCP timestamp support off, default 1, reduces CPU use
218	net.ipv4.tcp_timestamps = 0
219	# turn SACK support off, default on
220	# on systems with a VERY fast bus -> memory interface this is the big gainer
221	net.ipv4.tcp_sack = 0
222	# set min/default/max TCP read buffer, default 4096 87380 174760
223	net.ipv4.tcp_rmem = 10000000 10000000 10000000
224	# set min/pressure/max TCP write buffer, default 4096 16384 131072
225	net.ipv4.tcp_wmem = 10000000 10000000 10000000
226	# set min/pressure/max TCP buffer space, default 31744 32256 32768
227	net.ipv4.tcp_mem = 10000000 10000000 10000000
228	
229	### CORE settings (mostly for socket and UDP effect)
230	# set maximum receive socket buffer size, default 131071
231	net.core.rmem_max = 524287
232	# set maximum send socket buffer size, default 131071
233	net.core.wmem_max = 524287
234	# set default receive socket buffer size, default 65535
235	net.core.rmem_default = 524287
236	# set default send socket buffer size, default 65535
237	net.core.wmem_default = 524287
238	# set maximum amount of option memory buffers, default 10240
239	net.core.optmem_max = 524287
240	# set number of unprocessed input packets before kernel starts dropping them; default 300
241	net.core.netdev_max_backlog = 300000
242	- END sysctl_ixgb.conf
243	
244	Edit the ixgb_perf.sh script if necessary to change eth1 to whatever interface
245	your ixgb driver is using and/or replace '1a48' with appropriate 10GbE device's
246	ID installed on the system.
247	
248	NOTE: Unless these scripts are added to the boot process, these changes will
249	      only last only until the next system reboot.
250	
251	
252	Resolving Slow UDP Traffic
253	--------------------------
254	If your server does not seem to be able to receive UDP traffic as fast as it
255	can receive TCP traffic, it could be because Linux, by default, does not set
256	the network stack buffers as large as they need to be to support high UDP
257	transfer rates.  One way to alleviate this problem is to allow more memory to
258	be used by the IP stack to store incoming data.
259	
260	For instance, use the commands:
261	    sysctl -w net.core.rmem_max=262143
262	and
263	    sysctl -w net.core.rmem_default=262143
264	to increase the read buffer memory max and default to 262143 (256k - 1) from
265	defaults of max=131071 (128k - 1) and default=65535 (64k - 1).  These variables
266	will increase the amount of memory used by the network stack for receives, and
267	can be increased significantly more if necessary for your application.
268	
269	
270	Additional Configurations
271	=========================
272	
273	  Configuring the Driver on Different Distributions
274	  -------------------------------------------------
275	  Configuring a network driver to load properly when the system is started is
276	  distribution dependent. Typically, the configuration process involves adding
277	  an alias line to /etc/modprobe.conf as well as editing other system startup
278	  scripts and/or configuration files.  Many popular Linux distributions ship
279	  with tools to make these changes for you.  To learn the proper way to
280	  configure a network device for your system, refer to your distribution
281	  documentation.  If during this process you are asked for the driver or module
282	  name, the name for the Linux Base Driver for the Intel 10GbE Family of
283	  Adapters is ixgb.
284	
285	  Viewing Link Messages
286	  ---------------------
287	  Link messages will not be displayed to the console if the distribution is
288	  restricting system messages. In order to see network driver link messages on
289	  your console, set dmesg to eight by entering the following:
290	
291	       dmesg -n 8
292	
293	  NOTE: This setting is not saved across reboots.
294	
295	
296	  Jumbo Frames
297	  ------------
298	  The driver supports Jumbo Frames for all adapters. Jumbo Frames support is
299	  enabled by changing the MTU to a value larger than the default of 1500.
300	  The maximum value for the MTU is 16114.  Use the ifconfig command to
301	  increase the MTU size.  For example:
302	
303	        ifconfig ethx mtu 9000 up
304	
305	  The maximum MTU setting for Jumbo Frames is 16114.  This value coincides
306	  with the maximum Jumbo Frames size of 16128.
307	
308	
309	  ethtool
310	  -------
311	  The driver utilizes the ethtool interface for driver configuration and
312	  diagnostics, as well as displaying statistical information.  The ethtool
313	  version 1.6 or later is required for this functionality.
314	
315	  The latest release of ethtool can be found from
316	  http://ftp.kernel.org/pub/software/network/ethtool/
317	
318	  NOTE: The ethtool version 1.6 only supports a limited set of ethtool options.
319	        Support for a more complete ethtool feature set can be enabled by
320	        upgrading to the latest version.
321	
322	
323	  NAPI
324	  ----
325	
326	  NAPI (Rx polling mode) is supported in the ixgb driver.  NAPI is enabled
327	  or disabled based on the configuration of the kernel.  see CONFIG_IXGB_NAPI
328	
329	  See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.
330	
331	
332	Known Issues/Troubleshooting
333	============================
334	
335	  NOTE: After installing the driver, if your Intel Network Connection is not
336	  working, verify in the "In This Release" section of the readme that you have
337	  installed the correct driver.
338	
339	  Intel(R) PRO/10GbE CX4 Server Adapter Cable Interoperability Issue with
340	  Fujitsu XENPAK Module in SmartBits Chassis
341	  ---------------------------------------------------------------------
342	  Excessive CRC errors may be observed if the Intel(R) PRO/10GbE CX4
343	  Server adapter is connected to a Fujitsu XENPAK CX4 module in a SmartBits
344	  chassis using 15 m/24AWG cable assemblies manufactured by Fujitsu or Leoni.
345	  The CRC errors may be received either by the Intel(R) PRO/10GbE CX4
346	  Server adapter or the SmartBits. If this situation occurs using a different
347	  cable assembly may resolve the issue.
348	
349	  CX4 Server Adapter Cable Interoperability Issues with HP Procurve 3400cl
350	  Switch Port
351	  ------------------------------------------------------------------------
352	  Excessive CRC errors may be observed if the Intel(R) PRO/10GbE CX4 Server
353	  adapter is connected to an HP Procurve 3400cl switch port using short cables
354	  (1 m or shorter). If this situation occurs, using a longer cable may resolve
355	  the issue.
356	
357	  Excessive CRC errors may be observed using Fujitsu 24AWG cable assemblies that
358	  Are 10 m or longer or where using a Leoni 15 m/24AWG cable assembly. The CRC
359	  errors may be received either by the CX4 Server adapter or at the switch. If
360	  this situation occurs, using a different cable assembly may resolve the issue.
361	
362	
363	  Jumbo Frames System Requirement
364	  -------------------------------
365	  Memory allocation failures have been observed on Linux systems with 64 MB
366	  of RAM or less that are running Jumbo Frames.  If you are using Jumbo
367	  Frames, your system may require more than the advertised minimum
368	  requirement of 64 MB of system memory.
369	
370	
371	  Performance Degradation with Jumbo Frames
372	  -----------------------------------------
373	  Degradation in throughput performance may be observed in some Jumbo frames
374	  environments.  If this is observed, increasing the application's socket buffer
375	  size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
376	  See the specific application manual and /usr/src/linux*/Documentation/
377	  networking/ip-sysctl.txt for more details.
378	
379	
380	  Allocating Rx Buffers when Using Jumbo Frames
381	  ---------------------------------------------
382	  Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if
383	  the available memory is heavily fragmented. This issue may be seen with PCI-X
384	  adapters or with packet split disabled. This can be reduced or eliminated
385	  by changing the amount of available memory for receive buffer allocation, by
386	  increasing /proc/sys/vm/min_free_kbytes.
387	
388	
389	  Multiple Interfaces on Same Ethernet Broadcast Network
390	  ------------------------------------------------------
391	  Due to the default ARP behavior on Linux, it is not possible to have
392	  one system on two IP networks in the same Ethernet broadcast domain
393	  (non-partitioned switch) behave as expected.  All Ethernet interfaces
394	  will respond to IP traffic for any IP address assigned to the system.
395	  This results in unbalanced receive traffic.
396	
397	  If you have multiple interfaces in a server, do either of the following:
398	
399	  - Turn on ARP filtering by entering:
400	      echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
401	
402	  - Install the interfaces in separate broadcast domains - either in
403	    different switches or in a switch partitioned to VLANs.
404	
405	
406	  UDP Stress Test Dropped Packet Issue
407	  --------------------------------------
408	  Under small packets UDP stress test with 10GbE driver, the Linux system
409	  may drop UDP packets due to the fullness of socket buffers. You may want
410	  to change the driver's Flow Control variables to the minimum value for
411	  controlling packet reception.
412	
413	
414	  Tx Hangs Possible Under Stress
415	  ------------------------------
416	  Under stress conditions, if TX hangs occur, turning off TSO
417	  "ethtool -K eth0 tso off" may resolve the problem.
418	
419	
420	Support
421	=======
422	
423	For general information, go to the Intel support website at:
424	
425	    http://support.intel.com
426	
427	or the Intel Wired Networking project hosted by Sourceforge at:
428	
429	    http://sourceforge.net/projects/e1000
430	
431	If an issue is identified with the released source code on the supported
432	kernel with a supported adapter, email the specific information related
433	to the issue to e1000-devel@lists.sf.net
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