1 .. SPDX-License-Identifier: GPL-2.0+ 2 3 ========================================================== 4 Linux Base Driver for Intel(R) Ethernet Network Connection 5 ========================================================== 6 7 Intel Gigabit Linux driver. 8 Copyright(c) 1999 - 2013 Intel Corporation. 9 10 Contents 11 ======== 12 13 - Identifying Your Adapter 14 - Command Line Parameters 15 - Speed and Duplex Configuration 16 - Additional Configurations 17 - Support 18 19 Identifying Your Adapter 20 ======================== 21 22 For more information on how to identify your adapter, go to the Adapter & 23 Driver ID Guide at: 24 25 http://support.intel.com/support/go/network/adapter/idguide.htm 26 27 For the latest Intel network drivers for Linux, refer to the following 28 website. In the search field, enter your adapter name or type, or use the 29 networking link on the left to search for your adapter: 30 31 http://support.intel.com/support/go/network/adapter/home.htm 32 33 Command Line Parameters 34 ======================= 35 36 The default value for each parameter is generally the recommended setting, 37 unless otherwise noted. 38 39 NOTES: 40 For more information about the AutoNeg, Duplex, and Speed 41 parameters, see the "Speed and Duplex Configuration" section in 42 this document. 43 44 For more information about the InterruptThrottleRate, 45 RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay 46 parameters, see the application note at: 47 http://www.intel.com/design/network/applnots/ap450.htm 48 49 AutoNeg 50 ------- 51 52 (Supported only on adapters with copper connections) 53 54 :Valid Range: 0x01-0x0F, 0x20-0x2F 55 :Default Value: 0x2F 56 57 This parameter is a bit-mask that specifies the speed and duplex settings 58 advertised by the adapter. When this parameter is used, the Speed and 59 Duplex parameters must not be specified. 60 61 NOTE: 62 Refer to the Speed and Duplex section of this readme for more 63 information on the AutoNeg parameter. 64 65 Duplex 66 ------ 67 68 (Supported only on adapters with copper connections) 69 70 :Valid Range: 0-2 (0=auto-negotiate, 1=half, 2=full) 71 :Default Value: 0 72 73 This defines the direction in which data is allowed to flow. Can be 74 either one or two-directional. If both Duplex and the link partner are 75 set to auto-negotiate, the board auto-detects the correct duplex. If the 76 link partner is forced (either full or half), Duplex defaults to half- 77 duplex. 78 79 FlowControl 80 ----------- 81 82 :Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) 83 :Default Value: Reads flow control settings from the EEPROM 84 85 This parameter controls the automatic generation(Tx) and response(Rx) 86 to Ethernet PAUSE frames. 87 88 InterruptThrottleRate 89 --------------------- 90 91 (not supported on Intel(R) 82542, 82543 or 82544-based adapters) 92 93 :Valid Range: 94 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, 95 4=simplified balancing) 96 :Default Value: 3 97 98 The driver can limit the amount of interrupts per second that the adapter 99 will generate for incoming packets. It does this by writing a value to the 100 adapter that is based on the maximum amount of interrupts that the adapter 101 will generate per second. 102 103 Setting InterruptThrottleRate to a value greater or equal to 100 104 will program the adapter to send out a maximum of that many interrupts 105 per second, even if more packets have come in. This reduces interrupt 106 load on the system and can lower CPU utilization under heavy load, 107 but will increase latency as packets are not processed as quickly. 108 109 The default behaviour of the driver previously assumed a static 110 InterruptThrottleRate value of 8000, providing a good fallback value for 111 all traffic types,but lacking in small packet performance and latency. 112 The hardware can handle many more small packets per second however, and 113 for this reason an adaptive interrupt moderation algorithm was implemented. 114 115 Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which 116 it dynamically adjusts the InterruptThrottleRate value based on the traffic 117 that it receives. After determining the type of incoming traffic in the last 118 timeframe, it will adjust the InterruptThrottleRate to an appropriate value 119 for that traffic. 120 121 The algorithm classifies the incoming traffic every interval into 122 classes. Once the class is determined, the InterruptThrottleRate value is 123 adjusted to suit that traffic type the best. There are three classes defined: 124 "Bulk traffic", for large amounts of packets of normal size; "Low latency", 125 for small amounts of traffic and/or a significant percentage of small 126 packets; and "Lowest latency", for almost completely small packets or 127 minimal traffic. 128 129 In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 130 for traffic that falls in class "Bulk traffic". If traffic falls in the "Low 131 latency" or "Lowest latency" class, the InterruptThrottleRate is increased 132 stepwise to 20000. This default mode is suitable for most applications. 133 134 For situations where low latency is vital such as cluster or 135 grid computing, the algorithm can reduce latency even more when 136 InterruptThrottleRate is set to mode 1. In this mode, which operates 137 the same as mode 3, the InterruptThrottleRate will be increased stepwise to 138 70000 for traffic in class "Lowest latency". 139 140 In simplified mode the interrupt rate is based on the ratio of TX and 141 RX traffic. If the bytes per second rate is approximately equal, the 142 interrupt rate will drop as low as 2000 interrupts per second. If the 143 traffic is mostly transmit or mostly receive, the interrupt rate could 144 be as high as 8000. 145 146 Setting InterruptThrottleRate to 0 turns off any interrupt moderation 147 and may improve small packet latency, but is generally not suitable 148 for bulk throughput traffic. 149 150 NOTE: 151 InterruptThrottleRate takes precedence over the TxAbsIntDelay and 152 RxAbsIntDelay parameters. In other words, minimizing the receive 153 and/or transmit absolute delays does not force the controller to 154 generate more interrupts than what the Interrupt Throttle Rate 155 allows. 156 157 CAUTION: 158 If you are using the Intel(R) PRO/1000 CT Network Connection 159 (controller 82547), setting InterruptThrottleRate to a value 160 greater than 75,000, may hang (stop transmitting) adapters 161 under certain network conditions. If this occurs a NETDEV 162 WATCHDOG message is logged in the system event log. In 163 addition, the controller is automatically reset, restoring 164 the network connection. To eliminate the potential for the 165 hang, ensure that InterruptThrottleRate is set no greater 166 than 75,000 and is not set to 0. 167 168 NOTE: 169 When e1000 is loaded with default settings and multiple adapters 170 are in use simultaneously, the CPU utilization may increase non- 171 linearly. In order to limit the CPU utilization without impacting 172 the overall throughput, we recommend that you load the driver as 173 follows:: 174 175 modprobe e1000 InterruptThrottleRate=3000,3000,3000 176 177 This sets the InterruptThrottleRate to 3000 interrupts/sec for 178 the first, second, and third instances of the driver. The range 179 of 2000 to 3000 interrupts per second works on a majority of 180 systems and is a good starting point, but the optimal value will 181 be platform-specific. If CPU utilization is not a concern, use 182 RX_POLLING (NAPI) and default driver settings. 183 184 RxDescriptors 185 ------------- 186 187 :Valid Range: 188 - 48-256 for 82542 and 82543-based adapters 189 - 48-4096 for all other supported adapters 190 :Default Value: 256 191 192 This value specifies the number of receive buffer descriptors allocated 193 by the driver. Increasing this value allows the driver to buffer more 194 incoming packets, at the expense of increased system memory utilization. 195 196 Each descriptor is 16 bytes. A receive buffer is also allocated for each 197 descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending 198 on the MTU setting. The maximum MTU size is 16110. 199 200 NOTE: 201 MTU designates the frame size. It only needs to be set for Jumbo 202 Frames. Depending on the available system resources, the request 203 for a higher number of receive descriptors may be denied. In this 204 case, use a lower number. 205 206 RxIntDelay 207 ---------- 208 209 :Valid Range: 0-65535 (0=off) 210 :Default Value: 0 211 212 This value delays the generation of receive interrupts in units of 1.024 213 microseconds. Receive interrupt reduction can improve CPU efficiency if 214 properly tuned for specific network traffic. Increasing this value adds 215 extra latency to frame reception and can end up decreasing the throughput 216 of TCP traffic. If the system is reporting dropped receives, this value 217 may be set too high, causing the driver to run out of available receive 218 descriptors. 219 220 CAUTION: 221 When setting RxIntDelay to a value other than 0, adapters may 222 hang (stop transmitting) under certain network conditions. If 223 this occurs a NETDEV WATCHDOG message is logged in the system 224 event log. In addition, the controller is automatically reset, 225 restoring the network connection. To eliminate the potential 226 for the hang ensure that RxIntDelay is set to 0. 227 228 RxAbsIntDelay 229 ------------- 230 231 (This parameter is supported only on 82540, 82545 and later adapters.) 232 233 :Valid Range: 0-65535 (0=off) 234 :Default Value: 128 235 236 This value, in units of 1.024 microseconds, limits the delay in which a 237 receive interrupt is generated. Useful only if RxIntDelay is non-zero, 238 this value ensures that an interrupt is generated after the initial 239 packet is received within the set amount of time. Proper tuning, 240 along with RxIntDelay, may improve traffic throughput in specific network 241 conditions. 242 243 Speed 244 ----- 245 246 (This parameter is supported only on adapters with copper connections.) 247 248 :Valid Settings: 0, 10, 100, 1000 249 :Default Value: 0 (auto-negotiate at all supported speeds) 250 251 Speed forces the line speed to the specified value in megabits per second 252 (Mbps). If this parameter is not specified or is set to 0 and the link 253 partner is set to auto-negotiate, the board will auto-detect the correct 254 speed. Duplex should also be set when Speed is set to either 10 or 100. 255 256 TxDescriptors 257 ------------- 258 259 :Valid Range: 260 - 48-256 for 82542 and 82543-based adapters 261 - 48-4096 for all other supported adapters 262 :Default Value: 256 263 264 This value is the number of transmit descriptors allocated by the driver. 265 Increasing this value allows the driver to queue more transmits. Each 266 descriptor is 16 bytes. 267 268 NOTE: 269 Depending on the available system resources, the request for a 270 higher number of transmit descriptors may be denied. In this case, 271 use a lower number. 272 273 TxIntDelay 274 ---------- 275 276 :Valid Range: 0-65535 (0=off) 277 :Default Value: 8 278 279 This value delays the generation of transmit interrupts in units of 280 1.024 microseconds. Transmit interrupt reduction can improve CPU 281 efficiency if properly tuned for specific network traffic. If the 282 system is reporting dropped transmits, this value may be set too high 283 causing the driver to run out of available transmit descriptors. 284 285 TxAbsIntDelay 286 ------------- 287 288 (This parameter is supported only on 82540, 82545 and later adapters.) 289 290 :Valid Range: 0-65535 (0=off) 291 :Default Value: 32 292 293 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. 299 300 XsumRX 301 ------ 302 303 (This parameter is NOT supported on the 82542-based adapter.) 304 305 :Valid Range: 0-1 306 :Default Value: 1 307 308 A value of '1' indicates that the driver should enable IP checksum 309 offload for received packets (both UDP and TCP) to the adapter hardware. 310 311 Copybreak 312 --------- 313 314 :Valid Range: 0-xxxxxxx (0=off) 315 :Default Value: 256 316 :Usage: modprobe e1000.ko copybreak=128 317 318 Driver copies all packets below or equaling this size to a fresh RX 319 buffer before handing it up the stack. 320 321 This parameter is different than other parameters, in that it is a 322 single (not 1,1,1 etc.) parameter applied to all driver instances and 323 it is also available during runtime at 324 /sys/module/e1000/parameters/copybreak 325 326 SmartPowerDownEnable 327 -------------------- 328 329 :Valid Range: 0-1 330 :Default Value: 0 (disabled) 331 332 Allows PHY to turn off in lower power states. The user can turn off 333 this parameter in supported chipsets. 334 335 Speed and Duplex Configuration 336 ============================== 337 338 Three keywords are used to control the speed and duplex configuration. 339 These keywords are Speed, Duplex, and AutoNeg. 340 341 If the board uses a fiber interface, these keywords are ignored, and the 342 fiber interface board only links at 1000 Mbps full-duplex. 343 344 For copper-based boards, the keywords interact as follows: 345 346 - The default operation is auto-negotiate. The board advertises all 347 supported speed and duplex combinations, and it links at the highest 348 common speed and duplex mode IF the link partner is set to auto-negotiate. 349 350 - If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps 351 is advertised (The 1000BaseT spec requires auto-negotiation.) 352 353 - If Speed = 10 or 100, then both Speed and Duplex should be set. Auto- 354 negotiation is disabled, and the AutoNeg parameter is ignored. Partner 355 SHOULD also be forced. 356 357 The AutoNeg parameter is used when more control is required over the 358 auto-negotiation process. It should be used when you wish to control which 359 speed and duplex combinations are advertised during the auto-negotiation 360 process. 361 362 The parameter may be specified as either a decimal or hexadecimal value as 363 determined by the bitmap below. 364 365 ============== ====== ====== ======= ======= ====== ====== ======= ====== 366 Bit position 7 6 5 4 3 2 1 0 367 Decimal Value 128 64 32 16 8 4 2 1 368 Hex value 80 40 20 10 8 4 2 1 369 Speed (Mbps) N/A N/A 1000 N/A 100 100 10 10 370 Duplex Full Full Half Full Half 371 ============== ====== ====== ======= ======= ====== ====== ======= ====== 372 373 Some examples of using AutoNeg:: 374 375 modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half) 376 modprobe e1000 AutoNeg=1 (Same as above) 377 modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full) 378 modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full) 379 modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half) 380 modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100 381 Half) 382 modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full) 383 modprobe e1000 AutoNeg=32 (Same as above) 384 385 Note that when this parameter is used, Speed and Duplex must not be specified. 386 387 If the link partner is forced to a specific speed and duplex, then this 388 parameter should not be used. Instead, use the Speed and Duplex parameters 389 previously mentioned to force the adapter to the same speed and duplex. 390 391 Additional Configurations 392 ========================= 393 394 Jumbo Frames 395 ------------ 396 397 Jumbo Frames support is enabled by changing the MTU to a value larger than 398 the default of 1500. Use the ifconfig command to increase the MTU size. 399 For example:: 400 401 ifconfig eth<x> mtu 9000 up 402 403 This setting is not saved across reboots. It can be made permanent if 404 you add:: 405 406 MTU=9000 407 408 to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>. This example 409 applies to the Red Hat distributions; other distributions may store this 410 setting in a different location. 411 412 Notes: 413 Degradation in throughput performance may be observed in some Jumbo frames 414 environments. If this is observed, increasing the application's socket buffer 415 size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help. 416 See the specific application manual and /usr/src/linux*/Documentation/ 417 networking/ip-sysctl.txt for more details. 418 419 - The maximum MTU setting for Jumbo Frames is 16110. This value coincides 420 with the maximum Jumbo Frames size of 16128. 421 422 - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in 423 poor performance or loss of link. 424 425 - Adapters based on the Intel(R) 82542 and 82573V/E controller do not 426 support Jumbo Frames. These correspond to the following product names:: 427 428 Intel(R) PRO/1000 Gigabit Server Adapter 429 Intel(R) PRO/1000 PM Network Connection 430 431 ethtool 432 ------- 433 434 The driver utilizes the ethtool interface for driver configuration and 435 diagnostics, as well as displaying statistical information. The ethtool 436 version 1.6 or later is required for this functionality. 437 438 The latest release of ethtool can be found from 439 https://www.kernel.org/pub/software/network/ethtool/ 440 441 Enabling Wake on LAN (WoL) 442 -------------------------- 443 444 WoL is configured through the ethtool utility. 445 446 WoL will be enabled on the system during the next shut down or reboot. 447 For this driver version, in order to enable WoL, the e1000 driver must be 448 loaded when shutting down or rebooting the system. 449 450 Support 451 ======= 452 453 For general information, go to the Intel support website at: 454 http://support.intel.com 455 456 If an issue is identified with the released source code on the supported 457 kernel with a supported adapter, email the specific information related 458 to the issue to intel-wired-lan@lists.osuosl.org.
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