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Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.

1	Linux* Base Driver for Intel(R) Ethernet Network Connection
2	===========================================================
4	Intel Gigabit Linux driver.
5	Copyright(c) 1999 - 2013 Intel Corporation.
7	Contents
8	========
10	- Identifying Your Adapter
11	- Command Line Parameters
12	- Speed and Duplex Configuration
13	- Additional Configurations
14	- Support
16	Identifying Your Adapter
17	========================
19	For more information on how to identify your adapter, go to the Adapter &
20	Driver ID Guide at:
22	    http://support.intel.com/support/go/network/adapter/idguide.htm
24	For the latest Intel network drivers for Linux, refer to the following
25	website.  In the search field, enter your adapter name or type, or use the
26	networking link on the left to search for your adapter:
28	    http://support.intel.com/support/go/network/adapter/home.htm
30	Command Line Parameters
31	=======================
33	The default value for each parameter is generally the recommended setting,
34	unless otherwise noted.
36	NOTES:  For more information about the AutoNeg, Duplex, and Speed
37	        parameters, see the "Speed and Duplex Configuration" section in
38	        this document.
40	        For more information about the InterruptThrottleRate,
41	        RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay
42	        parameters, see the application note at:
43	        http://www.intel.com/design/network/applnots/ap450.htm
45	AutoNeg
46	-------
47	(Supported only on adapters with copper connections)
48	Valid Range:   0x01-0x0F, 0x20-0x2F
49	Default Value: 0x2F
51	This parameter is a bit-mask that specifies the speed and duplex settings
52	advertised by the adapter.  When this parameter is used, the Speed and
53	Duplex parameters must not be specified.
55	NOTE:  Refer to the Speed and Duplex section of this readme for more
56	       information on the AutoNeg parameter.
58	Duplex
59	------
60	(Supported only on adapters with copper connections)
61	Valid Range:   0-2 (0=auto-negotiate, 1=half, 2=full)
62	Default Value: 0
64	This defines the direction in which data is allowed to flow.  Can be
65	either one or two-directional.  If both Duplex and the link partner are
66	set to auto-negotiate, the board auto-detects the correct duplex.  If the
67	link partner is forced (either full or half), Duplex defaults to half-
68	duplex.
70	FlowControl
71	-----------
72	Valid Range:   0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)
73	Default Value: Reads flow control settings from the EEPROM
75	This parameter controls the automatic generation(Tx) and response(Rx)
76	to Ethernet PAUSE frames.
78	InterruptThrottleRate
79	---------------------
80	(not supported on Intel(R) 82542, 82543 or 82544-based adapters)
81	Valid Range:   0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative,
82	                                 4=simplified balancing)
83	Default Value: 3
85	The driver can limit the amount of interrupts per second that the adapter
86	will generate for incoming packets. It does this by writing a value to the
87	adapter that is based on the maximum amount of interrupts that the adapter
88	will generate per second.
90	Setting InterruptThrottleRate to a value greater or equal to 100
91	will program the adapter to send out a maximum of that many interrupts
92	per second, even if more packets have come in. This reduces interrupt
93	load on the system and can lower CPU utilization under heavy load,
94	but will increase latency as packets are not processed as quickly.
96	The default behaviour of the driver previously assumed a static
97	InterruptThrottleRate value of 8000, providing a good fallback value for
98	all traffic types,but lacking in small packet performance and latency.
99	The hardware can handle many more small packets per second however, and
100	for this reason an adaptive interrupt moderation algorithm was implemented.
102	Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which
103	it dynamically adjusts the InterruptThrottleRate value based on the traffic
104	that it receives. After determining the type of incoming traffic in the last
105	timeframe, it will adjust the InterruptThrottleRate to an appropriate value
106	for that traffic.
108	The algorithm classifies the incoming traffic every interval into
109	classes.  Once the class is determined, the InterruptThrottleRate value is
110	adjusted to suit that traffic type the best. There are three classes defined:
111	"Bulk traffic", for large amounts of packets of normal size; "Low latency",
112	for small amounts of traffic and/or a significant percentage of small
113	packets; and "Lowest latency", for almost completely small packets or
114	minimal traffic.
116	In dynamic conservative mode, the InterruptThrottleRate value is set to 4000
117	for traffic that falls in class "Bulk traffic". If traffic falls in the "Low
118	latency" or "Lowest latency" class, the InterruptThrottleRate is increased
119	stepwise to 20000. This default mode is suitable for most applications.
121	For situations where low latency is vital such as cluster or
122	grid computing, the algorithm can reduce latency even more when
123	InterruptThrottleRate is set to mode 1. In this mode, which operates
124	the same as mode 3, the InterruptThrottleRate will be increased stepwise to
125	70000 for traffic in class "Lowest latency".
127	In simplified mode the interrupt rate is based on the ratio of TX and
128	RX traffic.  If the bytes per second rate is approximately equal, the
129	interrupt rate will drop as low as 2000 interrupts per second.  If the
130	traffic is mostly transmit or mostly receive, the interrupt rate could
131	be as high as 8000.
133	Setting InterruptThrottleRate to 0 turns off any interrupt moderation
134	and may improve small packet latency, but is generally not suitable
135	for bulk throughput traffic.
137	NOTE:  InterruptThrottleRate takes precedence over the TxAbsIntDelay and
138	       RxAbsIntDelay parameters.  In other words, minimizing the receive
139	       and/or transmit absolute delays does not force the controller to
140	       generate more interrupts than what the Interrupt Throttle Rate
141	       allows.
143	CAUTION:  If you are using the Intel(R) PRO/1000 CT Network Connection
144	          (controller 82547), setting InterruptThrottleRate to a value
145	          greater than 75,000, may hang (stop transmitting) adapters
146	          under certain network conditions.  If this occurs a NETDEV
147	          WATCHDOG message is logged in the system event log.  In
148	          addition, the controller is automatically reset, restoring
149	          the network connection.  To eliminate the potential for the
150	          hang, ensure that InterruptThrottleRate is set no greater
151	          than 75,000 and is not set to 0.
153	NOTE:  When e1000 is loaded with default settings and multiple adapters
154	       are in use simultaneously, the CPU utilization may increase non-
155	       linearly.  In order to limit the CPU utilization without impacting
156	       the overall throughput, we recommend that you load the driver as
157	       follows:
159	           modprobe e1000 InterruptThrottleRate=3000,3000,3000
161	       This sets the InterruptThrottleRate to 3000 interrupts/sec for
162	       the first, second, and third instances of the driver.  The range
163	       of 2000 to 3000 interrupts per second works on a majority of
164	       systems and is a good starting point, but the optimal value will
165	       be platform-specific.  If CPU utilization is not a concern, use
166	       RX_POLLING (NAPI) and default driver settings.
168	RxDescriptors
169	-------------
170	Valid Range:   80-256 for 82542 and 82543-based adapters
171	               80-4096 for all other supported adapters
172	Default Value: 256
174	This value specifies the number of receive buffer descriptors allocated
175	by the driver.  Increasing this value allows the driver to buffer more
176	incoming packets, at the expense of increased system memory utilization.
178	Each descriptor is 16 bytes.  A receive buffer is also allocated for each
179	descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending
180	on the MTU setting. The maximum MTU size is 16110.
182	NOTE:  MTU designates the frame size.  It only needs to be set for Jumbo
183	       Frames.  Depending on the available system resources, the request
184	       for a higher number of receive descriptors may be denied.  In this
185	       case, use a lower number.
187	RxIntDelay
188	----------
189	Valid Range:   0-65535 (0=off)
190	Default Value: 0
192	This value delays the generation of receive interrupts in units of 1.024
193	microseconds.  Receive interrupt reduction can improve CPU efficiency if
194	properly tuned for specific network traffic.  Increasing this value adds
195	extra latency to frame reception and can end up decreasing the throughput
196	of TCP traffic.  If the system is reporting dropped receives, this value
197	may be set too high, causing the driver to run out of available receive
198	descriptors.
200	CAUTION:  When setting RxIntDelay to a value other than 0, adapters may
201	          hang (stop transmitting) under certain network conditions.  If
202	          this occurs a NETDEV WATCHDOG message is logged in the system
203	          event log.  In addition, the controller is automatically reset,
204	          restoring the network connection.  To eliminate the potential
205	          for the hang ensure that RxIntDelay is set to 0.
207	RxAbsIntDelay
208	-------------
209	(This parameter is supported only on 82540, 82545 and later adapters.)
210	Valid Range:   0-65535 (0=off)
211	Default Value: 128
213	This value, in units of 1.024 microseconds, limits the delay in which a
214	receive interrupt is generated.  Useful only if RxIntDelay is non-zero,
215	this value ensures that an interrupt is generated after the initial
216	packet is received within the set amount of time.  Proper tuning,
217	along with RxIntDelay, may improve traffic throughput in specific network
218	conditions.
220	Speed
221	-----
222	(This parameter is supported only on adapters with copper connections.)
223	Valid Settings: 0, 10, 100, 1000
224	Default Value:  0 (auto-negotiate at all supported speeds)
226	Speed forces the line speed to the specified value in megabits per second
227	(Mbps).  If this parameter is not specified or is set to 0 and the link
228	partner is set to auto-negotiate, the board will auto-detect the correct
229	speed.  Duplex should also be set when Speed is set to either 10 or 100.
231	TxDescriptors
232	-------------
233	Valid Range:   80-256 for 82542 and 82543-based adapters
234	               80-4096 for all other supported adapters
235	Default Value: 256
237	This value is the number of transmit descriptors allocated by the driver.
238	Increasing this value allows the driver to queue more transmits.  Each
239	descriptor is 16 bytes.
241	NOTE:  Depending on the available system resources, the request for a
242	       higher number of transmit descriptors may be denied.  In this case,
243	       use a lower number.
245	TxDescriptorStep
246	----------------
247	Valid Range:    1 (use every Tx Descriptor)
248	                4 (use every 4th Tx Descriptor)
250	Default Value:  1 (use every Tx Descriptor)
252	On certain non-Intel architectures, it has been observed that intense TX
253	traffic bursts of short packets may result in an improper descriptor
254	writeback. If this occurs, the driver will report a "TX Timeout" and reset
255	the adapter, after which the transmit flow will restart, though data may
256	have stalled for as much as 10 seconds before it resumes.
258	The improper writeback does not occur on the first descriptor in a system
259	memory cache-line, which is typically 32 bytes, or 4 descriptors long.
261	Setting TxDescriptorStep to a value of 4 will ensure that all TX descriptors
262	are aligned to the start of a system memory cache line, and so this problem
263	will not occur.
265	NOTES: Setting TxDescriptorStep to 4 effectively reduces the number of
266	       TxDescriptors available for transmits to 1/4 of the normal allocation.
267	       This has a possible negative performance impact, which may be
268	       compensated for by allocating more descriptors using the TxDescriptors
269	       module parameter.
271	       There are other conditions which may result in "TX Timeout", which will
272	       not be resolved by the use of the TxDescriptorStep parameter. As the
273	       issue addressed by this parameter has never been observed on Intel
274	       Architecture platforms, it should not be used on Intel platforms.
276	TxIntDelay
277	----------
278	Valid Range:   0-65535 (0=off)
279	Default Value: 64
281	This value delays the generation of transmit interrupts in units of
282	1.024 microseconds.  Transmit interrupt reduction can improve CPU
283	efficiency if properly tuned for specific network traffic.  If the
284	system is reporting dropped transmits, this value may be set too high
285	causing the driver to run out of available transmit descriptors.
287	TxAbsIntDelay
288	-------------
289	(This parameter is supported only on 82540, 82545 and later adapters.)
290	Valid Range:   0-65535 (0=off)
291	Default Value: 64
293	This value, in units of 1.024 microseconds, limits the delay in which a
294	transmit interrupt is generated.  Useful only if TxIntDelay is non-zero,
295	this value ensures that an interrupt is generated after the initial
296	packet is sent on the wire within the set amount of time.  Proper tuning,
297	along with TxIntDelay, may improve traffic throughput in specific
298	network conditions.
300	XsumRX
301	------
302	(This parameter is NOT supported on the 82542-based adapter.)
303	Valid Range:   0-1
304	Default Value: 1
306	A value of '1' indicates that the driver should enable IP checksum
307	offload for received packets (both UDP and TCP) to the adapter hardware.
309	Copybreak
310	---------
311	Valid Range:   0-xxxxxxx (0=off)
312	Default Value: 256
313	Usage: insmod e1000.ko copybreak=128
315	Driver copies all packets below or equaling this size to a fresh RX
316	buffer before handing it up the stack.
318	This parameter is different than other parameters, in that it is a
319	single (not 1,1,1 etc.) parameter applied to all driver instances and
320	it is also available during runtime at
321	/sys/module/e1000/parameters/copybreak
323	SmartPowerDownEnable
324	--------------------
325	Valid Range: 0-1
326	Default Value:  0 (disabled)
328	Allows PHY to turn off in lower power states. The user can turn off
329	this parameter in supported chipsets.
331	KumeranLockLoss
332	---------------
333	Valid Range: 0-1
334	Default Value: 1 (enabled)
336	This workaround skips resetting the PHY at shutdown for the initial
337	silicon releases of ICH8 systems.
339	Speed and Duplex Configuration
340	==============================
342	Three keywords are used to control the speed and duplex configuration.
343	These keywords are Speed, Duplex, and AutoNeg.
345	If the board uses a fiber interface, these keywords are ignored, and the
346	fiber interface board only links at 1000 Mbps full-duplex.
348	For copper-based boards, the keywords interact as follows:
350	  The default operation is auto-negotiate.  The board advertises all
351	  supported speed and duplex combinations, and it links at the highest
352	  common speed and duplex mode IF the link partner is set to auto-negotiate.
354	  If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps
355	  is advertised (The 1000BaseT spec requires auto-negotiation.)
357	  If Speed = 10 or 100, then both Speed and Duplex should be set.  Auto-
358	  negotiation is disabled, and the AutoNeg parameter is ignored.  Partner
359	  SHOULD also be forced.
361	The AutoNeg parameter is used when more control is required over the
362	auto-negotiation process.  It should be used when you wish to control which
363	speed and duplex combinations are advertised during the auto-negotiation
364	process.
366	The parameter may be specified as either a decimal or hexadecimal value as
367	determined by the bitmap below.
369	Bit position   7      6      5       4       3      2      1       0
370	Decimal Value  128    64     32      16      8      4      2       1
371	Hex value      80     40     20      10      8      4      2       1
372	Speed (Mbps)   N/A    N/A    1000    N/A     100    100    10      10
373	Duplex                       Full            Full   Half   Full    Half
375	Some examples of using AutoNeg:
377	  modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half)
378	  modprobe e1000 AutoNeg=1 (Same as above)
379	  modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full)
380	  modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full)
381	  modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half)
382	  modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100
383	  Half)
384	  modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)
385	  modprobe e1000 AutoNeg=32 (Same as above)
387	Note that when this parameter is used, Speed and Duplex must not be specified.
389	If the link partner is forced to a specific speed and duplex, then this
390	parameter should not be used.  Instead, use the Speed and Duplex parameters
391	previously mentioned to force the adapter to the same speed and duplex.
393	Additional Configurations
394	=========================
396	  Jumbo Frames
397	  ------------
398	  Jumbo Frames support is enabled by changing the MTU to a value larger than
399	  the default of 1500.  Use the ifconfig command to increase the MTU size.
400	  For example:
402	       ifconfig eth<x> mtu 9000 up
404	  This setting is not saved across reboots.  It can be made permanent if
405	  you add:
407	       MTU=9000
409	   to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>.  This example
410	   applies to the Red Hat distributions; other distributions may store this
411	   setting in a different location.
413	  Notes:
414	  Degradation in throughput performance may be observed in some Jumbo frames
415	  environments. If this is observed, increasing the application's socket buffer
416	  size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
417	  See the specific application manual and /usr/src/linux*/Documentation/
418	  networking/ip-sysctl.txt for more details.
420	  - The maximum MTU setting for Jumbo Frames is 16110.  This value coincides
421	    with the maximum Jumbo Frames size of 16128.
423	  - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in
424	    poor performance or loss of link.
426	  - Adapters based on the Intel(R) 82542 and 82573V/E controller do not
427	    support Jumbo Frames. These correspond to the following product names:
428	     Intel(R) PRO/1000 Gigabit Server Adapter
429	     Intel(R) PRO/1000 PM Network Connection
431	  ethtool
432	  -------
433	  The driver utilizes the ethtool interface for driver configuration and
434	  diagnostics, as well as displaying statistical information.  The ethtool
435	  version 1.6 or later is required for this functionality.
437	  The latest release of ethtool can be found from
438	  https://www.kernel.org/pub/software/network/ethtool/
440	  Enabling Wake on LAN* (WoL)
441	  ---------------------------
442	  WoL is configured through the ethtool* utility.
444	  WoL will be enabled on the system during the next shut down or reboot.
445	  For this driver version, in order to enable WoL, the e1000 driver must be
446	  loaded when shutting down or rebooting the system.
448	Support
449	=======
451	For general information, go to the Intel support website at:
453	    http://support.intel.com
455	or the Intel Wired Networking project hosted by Sourceforge at:
457	    http://sourceforge.net/projects/e1000
459	If an issue is identified with the released source code on the supported
460	kernel with a supported adapter, email the specific information related
461	to the issue to e1000-devel@lists.sf.net
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