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1 | Linux* Driver for Intel(R) Network Connection | ||
2 | =============================================================== | ||
3 | |||
4 | Intel Gigabit Linux driver. | ||
5 | Copyright(c) 1999 - 2010 Intel Corporation. | ||
6 | |||
7 | Contents | ||
8 | ======== | ||
9 | |||
10 | - Identifying Your Adapter | ||
11 | - Command Line Parameters | ||
12 | - Additional Configurations | ||
13 | - Support | ||
14 | |||
15 | Identifying Your Adapter | ||
16 | ======================== | ||
17 | |||
18 | The e1000e driver supports all PCI Express Intel(R) Gigabit Network | ||
19 | Connections, except those that are 82575, 82576 and 82580-based*. | ||
20 | |||
21 | * NOTE: The Intel(R) PRO/1000 P Dual Port Server Adapter is supported by | ||
22 | the e1000 driver, not the e1000e driver due to the 82546 part being used | ||
23 | behind a PCI Express bridge. | ||
24 | |||
25 | For more information on how to identify your adapter, go to the Adapter & | ||
26 | Driver ID Guide at: | ||
27 | |||
28 | http://support.intel.com/support/go/network/adapter/idguide.htm | ||
29 | |||
30 | For the latest Intel network drivers for Linux, refer to the following | ||
31 | website. In the search field, enter your adapter name or type, or use the | ||
32 | networking link on the left to search for your adapter: | ||
33 | |||
34 | http://support.intel.com/support/go/network/adapter/home.htm | ||
35 | |||
36 | Command Line Parameters | ||
37 | ======================= | ||
38 | |||
39 | The default value for each parameter is generally the recommended setting, | ||
40 | unless otherwise noted. | ||
41 | |||
42 | NOTES: For more information about the InterruptThrottleRate, | ||
43 | RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay | ||
44 | parameters, see the application note at: | ||
45 | http://www.intel.com/design/network/applnots/ap450.htm | ||
46 | |||
47 | InterruptThrottleRate | ||
48 | --------------------- | ||
49 | Valid Range: 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, | ||
50 | 4=simplified balancing) | ||
51 | Default Value: 3 | ||
52 | |||
53 | The driver can limit the amount of interrupts per second that the adapter | ||
54 | will generate for incoming packets. It does this by writing a value to the | ||
55 | adapter that is based on the maximum amount of interrupts that the adapter | ||
56 | will generate per second. | ||
57 | |||
58 | Setting InterruptThrottleRate to a value greater or equal to 100 | ||
59 | will program the adapter to send out a maximum of that many interrupts | ||
60 | per second, even if more packets have come in. This reduces interrupt | ||
61 | load on the system and can lower CPU utilization under heavy load, | ||
62 | but will increase latency as packets are not processed as quickly. | ||
63 | |||
64 | The driver has two adaptive modes (setting 1 or 3) in which | ||
65 | it dynamically adjusts the InterruptThrottleRate value based on the traffic | ||
66 | that it receives. After determining the type of incoming traffic in the last | ||
67 | timeframe, it will adjust the InterruptThrottleRate to an appropriate value | ||
68 | for that traffic. | ||
69 | |||
70 | The algorithm classifies the incoming traffic every interval into | ||
71 | classes. Once the class is determined, the InterruptThrottleRate value is | ||
72 | adjusted to suit that traffic type the best. There are three classes defined: | ||
73 | "Bulk traffic", for large amounts of packets of normal size; "Low latency", | ||
74 | for small amounts of traffic and/or a significant percentage of small | ||
75 | packets; and "Lowest latency", for almost completely small packets or | ||
76 | minimal traffic. | ||
77 | |||
78 | In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 | ||
79 | for traffic that falls in class "Bulk traffic". If traffic falls in the "Low | ||
80 | latency" or "Lowest latency" class, the InterruptThrottleRate is increased | ||
81 | stepwise to 20000. This default mode is suitable for most applications. | ||
82 | |||
83 | For situations where low latency is vital such as cluster or | ||
84 | grid computing, the algorithm can reduce latency even more when | ||
85 | InterruptThrottleRate is set to mode 1. In this mode, which operates | ||
86 | the same as mode 3, the InterruptThrottleRate will be increased stepwise to | ||
87 | 70000 for traffic in class "Lowest latency". | ||
88 | |||
89 | In simplified mode the interrupt rate is based on the ratio of Tx and | ||
90 | Rx traffic. If the bytes per second rate is approximately equal the | ||
91 | interrupt rate will drop as low as 2000 interrupts per second. If the | ||
92 | traffic is mostly transmit or mostly receive, the interrupt rate could | ||
93 | be as high as 8000. | ||
94 | |||
95 | Setting InterruptThrottleRate to 0 turns off any interrupt moderation | ||
96 | and may improve small packet latency, but is generally not suitable | ||
97 | for bulk throughput traffic. | ||
98 | |||
99 | NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and | ||
100 | RxAbsIntDelay parameters. In other words, minimizing the receive | ||
101 | and/or transmit absolute delays does not force the controller to | ||
102 | generate more interrupts than what the Interrupt Throttle Rate | ||
103 | allows. | ||
104 | |||
105 | NOTE: When e1000e is loaded with default settings and multiple adapters | ||
106 | are in use simultaneously, the CPU utilization may increase non- | ||
107 | linearly. In order to limit the CPU utilization without impacting | ||
108 | the overall throughput, we recommend that you load the driver as | ||
109 | follows: | ||
110 | |||
111 | modprobe e1000e InterruptThrottleRate=3000,3000,3000 | ||
112 | |||
113 | This sets the InterruptThrottleRate to 3000 interrupts/sec for | ||
114 | the first, second, and third instances of the driver. The range | ||
115 | of 2000 to 3000 interrupts per second works on a majority of | ||
116 | systems and is a good starting point, but the optimal value will | ||
117 | be platform-specific. If CPU utilization is not a concern, use | ||
118 | RX_POLLING (NAPI) and default driver settings. | ||
119 | |||
120 | RxIntDelay | ||
121 | ---------- | ||
122 | Valid Range: 0-65535 (0=off) | ||
123 | Default Value: 0 | ||
124 | |||
125 | This value delays the generation of receive interrupts in units of 1.024 | ||
126 | microseconds. Receive interrupt reduction can improve CPU efficiency if | ||
127 | properly tuned for specific network traffic. Increasing this value adds | ||
128 | extra latency to frame reception and can end up decreasing the throughput | ||
129 | of TCP traffic. If the system is reporting dropped receives, this value | ||
130 | may be set too high, causing the driver to run out of available receive | ||
131 | descriptors. | ||
132 | |||
133 | CAUTION: When setting RxIntDelay to a value other than 0, adapters may | ||
134 | hang (stop transmitting) under certain network conditions. If | ||
135 | this occurs a NETDEV WATCHDOG message is logged in the system | ||
136 | event log. In addition, the controller is automatically reset, | ||
137 | restoring the network connection. To eliminate the potential | ||
138 | for the hang ensure that RxIntDelay is set to 0. | ||
139 | |||
140 | RxAbsIntDelay | ||
141 | ------------- | ||
142 | Valid Range: 0-65535 (0=off) | ||
143 | Default Value: 8 | ||
144 | |||
145 | This value, in units of 1.024 microseconds, limits the delay in which a | ||
146 | receive interrupt is generated. Useful only if RxIntDelay is non-zero, | ||
147 | this value ensures that an interrupt is generated after the initial | ||
148 | packet is received within the set amount of time. Proper tuning, | ||
149 | along with RxIntDelay, may improve traffic throughput in specific network | ||
150 | conditions. | ||
151 | |||
152 | TxIntDelay | ||
153 | ---------- | ||
154 | Valid Range: 0-65535 (0=off) | ||
155 | Default Value: 8 | ||
156 | |||
157 | This value delays the generation of transmit interrupts in units of | ||
158 | 1.024 microseconds. Transmit interrupt reduction can improve CPU | ||
159 | efficiency if properly tuned for specific network traffic. If the | ||
160 | system is reporting dropped transmits, this value may be set too high | ||
161 | causing the driver to run out of available transmit descriptors. | ||
162 | |||
163 | TxAbsIntDelay | ||
164 | ------------- | ||
165 | Valid Range: 0-65535 (0=off) | ||
166 | Default Value: 32 | ||
167 | |||
168 | This value, in units of 1.024 microseconds, limits the delay in which a | ||
169 | transmit interrupt is generated. Useful only if TxIntDelay is non-zero, | ||
170 | this value ensures that an interrupt is generated after the initial | ||
171 | packet is sent on the wire within the set amount of time. Proper tuning, | ||
172 | along with TxIntDelay, may improve traffic throughput in specific | ||
173 | network conditions. | ||
174 | |||
175 | Copybreak | ||
176 | --------- | ||
177 | Valid Range: 0-xxxxxxx (0=off) | ||
178 | Default Value: 256 | ||
179 | |||
180 | Driver copies all packets below or equaling this size to a fresh Rx | ||
181 | buffer before handing it up the stack. | ||
182 | |||
183 | This parameter is different than other parameters, in that it is a | ||
184 | single (not 1,1,1 etc.) parameter applied to all driver instances and | ||
185 | it is also available during runtime at | ||
186 | /sys/module/e1000e/parameters/copybreak | ||
187 | |||
188 | SmartPowerDownEnable | ||
189 | -------------------- | ||
190 | Valid Range: 0-1 | ||
191 | Default Value: 0 (disabled) | ||
192 | |||
193 | Allows PHY to turn off in lower power states. The user can set this parameter | ||
194 | in supported chipsets. | ||
195 | |||
196 | KumeranLockLoss | ||
197 | --------------- | ||
198 | Valid Range: 0-1 | ||
199 | Default Value: 1 (enabled) | ||
200 | |||
201 | This workaround skips resetting the PHY at shutdown for the initial | ||
202 | silicon releases of ICH8 systems. | ||
203 | |||
204 | IntMode | ||
205 | ------- | ||
206 | Valid Range: 0-2 (0=legacy, 1=MSI, 2=MSI-X) | ||
207 | Default Value: 2 | ||
208 | |||
209 | Allows changing the interrupt mode at module load time, without requiring a | ||
210 | recompile. If the driver load fails to enable a specific interrupt mode, the | ||
211 | driver will try other interrupt modes, from least to most compatible. The | ||
212 | interrupt order is MSI-X, MSI, Legacy. If specifying MSI (IntMode=1) | ||
213 | interrupts, only MSI and Legacy will be attempted. | ||
214 | |||
215 | CrcStripping | ||
216 | ------------ | ||
217 | Valid Range: 0-1 | ||
218 | Default Value: 1 (enabled) | ||
219 | |||
220 | Strip the CRC from received packets before sending up the network stack. If | ||
221 | you have a machine with a BMC enabled but cannot receive IPMI traffic after | ||
222 | loading or enabling the driver, try disabling this feature. | ||
223 | |||
224 | WriteProtectNVM | ||
225 | --------------- | ||
226 | Valid Range: 0-1 | ||
227 | Default Value: 1 (enabled) | ||
228 | |||
229 | Set the hardware to ignore all write/erase cycles to the GbE region in the | ||
230 | ICHx NVM (non-volatile memory). This feature can be disabled by the | ||
231 | WriteProtectNVM module parameter (enabled by default) only after a hardware | ||
232 | reset, but the machine must be power cycled before trying to enable writes. | ||
233 | |||
234 | Note: the kernel boot option iomem=relaxed may need to be set if the kernel | ||
235 | config option CONFIG_STRICT_DEVMEM=y, if the root user wants to write the | ||
236 | NVM from user space via ethtool. | ||
237 | |||
238 | Additional Configurations | ||
239 | ========================= | ||
240 | |||
241 | Jumbo Frames | ||
242 | ------------ | ||
243 | Jumbo Frames support is enabled by changing the MTU to a value larger than | ||
244 | the default of 1500. Use the ifconfig command to increase the MTU size. | ||
245 | For example: | ||
246 | |||
247 | ifconfig eth<x> mtu 9000 up | ||
248 | |||
249 | This setting is not saved across reboots. | ||
250 | |||
251 | Notes: | ||
252 | |||
253 | - The maximum MTU setting for Jumbo Frames is 9216. This value coincides | ||
254 | with the maximum Jumbo Frames size of 9234 bytes. | ||
255 | |||
256 | - Using Jumbo Frames at 10 or 100 Mbps is not supported and may result in | ||
257 | poor performance or loss of link. | ||
258 | |||
259 | - Some adapters limit Jumbo Frames sized packets to a maximum of | ||
260 | 4096 bytes and some adapters do not support Jumbo Frames. | ||
261 | |||
262 | |||
263 | Ethtool | ||
264 | ------- | ||
265 | The driver utilizes the ethtool interface for driver configuration and | ||
266 | diagnostics, as well as displaying statistical information. We | ||
267 | strongly recommend downloading the latest version of Ethtool at: | ||
268 | |||
269 | http://sourceforge.net/projects/gkernel. | ||
270 | |||
271 | Speed and Duplex | ||
272 | ---------------- | ||
273 | Speed and Duplex are configured through the Ethtool* utility. For | ||
274 | instructions, refer to the Ethtool man page. | ||
275 | |||
276 | Enabling Wake on LAN* (WoL) | ||
277 | --------------------------- | ||
278 | WoL is configured through the Ethtool* utility. For instructions on | ||
279 | enabling WoL with Ethtool, refer to the Ethtool man page. | ||
280 | |||
281 | WoL will be enabled on the system during the next shut down or reboot. | ||
282 | For this driver version, in order to enable WoL, the e1000e driver must be | ||
283 | loaded when shutting down or rebooting the system. | ||
284 | |||
285 | In most cases Wake On LAN is only supported on port A for multiple port | ||
286 | adapters. To verify if a port supports Wake on LAN run ethtool eth<X>. | ||
287 | |||
288 | |||
289 | Support | ||
290 | ======= | ||
291 | |||
292 | For general information, go to the Intel support website at: | ||
293 | |||
294 | www.intel.com/support/ | ||
295 | |||
296 | or the Intel Wired Networking project hosted by Sourceforge at: | ||
297 | |||
298 | http://sourceforge.net/projects/e1000 | ||
299 | |||
300 | If an issue is identified with the released source code on the supported | ||
301 | kernel with a supported adapter, email the specific information related | ||
302 | to the issue to e1000-devel@lists.sf.net | ||