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1.. SPDX-License-Identifier: GPL-2.0+2 3==========================================================4Linux Base Driver for Intel(R) Ethernet Network Connection5==========================================================6 7Intel Gigabit Linux driver.8Copyright(c) 1999 - 2013 Intel Corporation.9 10Contents11========12 13- Identifying Your Adapter14- Command Line Parameters15- Speed and Duplex Configuration16- Additional Configurations17- Support18 19Identifying Your Adapter20========================21 22For more information on how to identify your adapter, go to the Adapter &23Driver ID Guide at:24 25 http://support.intel.com/support/go/network/adapter/idguide.htm26 27For the latest Intel network drivers for Linux, refer to the following28website. In the search field, enter your adapter name or type, or use the29networking link on the left to search for your adapter:30 31 http://support.intel.com/support/go/network/adapter/home.htm32 33Command Line Parameters34=======================35 36The default value for each parameter is generally the recommended setting,37unless otherwise noted.38 39NOTES:40 For more information about the AutoNeg, Duplex, and Speed41 parameters, see the "Speed and Duplex Configuration" section in42 this document.43 44 For more information about the InterruptThrottleRate,45 RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay46 parameters, see the application note at:47 http://www.intel.com/design/network/applnots/ap450.htm48 49AutoNeg50-------51 52(Supported only on adapters with copper connections)53 54:Valid Range: 0x01-0x0F, 0x20-0x2F55:Default Value: 0x2F56 57This parameter is a bit-mask that specifies the speed and duplex settings58advertised by the adapter. When this parameter is used, the Speed and59Duplex parameters must not be specified.60 61NOTE:62 Refer to the Speed and Duplex section of this readme for more63 information on the AutoNeg parameter.64 65Duplex66------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: 072 73This defines the direction in which data is allowed to flow. Can be74either one or two-directional. If both Duplex and the link partner are75set to auto-negotiate, the board auto-detects the correct duplex. If the76link partner is forced (either full or half), Duplex defaults to half-77duplex.78 79FlowControl80-----------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 EEPROM84 85This parameter controls the automatic generation(Tx) and response(Rx)86to Ethernet PAUSE frames.87 88InterruptThrottleRate89---------------------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: 397 98The driver can limit the amount of interrupts per second that the adapter99will generate for incoming packets. It does this by writing a value to the100adapter that is based on the maximum amount of interrupts that the adapter101will generate per second.102 103Setting InterruptThrottleRate to a value greater or equal to 100104will program the adapter to send out a maximum of that many interrupts105per second, even if more packets have come in. This reduces interrupt106load on the system and can lower CPU utilization under heavy load,107but will increase latency as packets are not processed as quickly.108 109The default behaviour of the driver previously assumed a static110InterruptThrottleRate value of 8000, providing a good fallback value for111all traffic types,but lacking in small packet performance and latency.112The hardware can handle many more small packets per second however, and113for this reason an adaptive interrupt moderation algorithm was implemented.114 115Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which116it dynamically adjusts the InterruptThrottleRate value based on the traffic117that it receives. After determining the type of incoming traffic in the last118timeframe, it will adjust the InterruptThrottleRate to an appropriate value119for that traffic.120 121The algorithm classifies the incoming traffic every interval into122classes. Once the class is determined, the InterruptThrottleRate value is123adjusted 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",125for small amounts of traffic and/or a significant percentage of small126packets; and "Lowest latency", for almost completely small packets or127minimal traffic.128 129In dynamic conservative mode, the InterruptThrottleRate value is set to 4000130for traffic that falls in class "Bulk traffic". If traffic falls in the "Low131latency" or "Lowest latency" class, the InterruptThrottleRate is increased132stepwise to 20000. This default mode is suitable for most applications.133 134For situations where low latency is vital such as cluster or135grid computing, the algorithm can reduce latency even more when136InterruptThrottleRate is set to mode 1. In this mode, which operates137the same as mode 3, the InterruptThrottleRate will be increased stepwise to13870000 for traffic in class "Lowest latency".139 140In simplified mode the interrupt rate is based on the ratio of TX and141RX traffic. If the bytes per second rate is approximately equal, the142interrupt rate will drop as low as 2000 interrupts per second. If the143traffic is mostly transmit or mostly receive, the interrupt rate could144be as high as 8000.145 146Setting InterruptThrottleRate to 0 turns off any interrupt moderation147and may improve small packet latency, but is generally not suitable148for bulk throughput traffic.149 150NOTE:151 InterruptThrottleRate takes precedence over the TxAbsIntDelay and152 RxAbsIntDelay parameters. In other words, minimizing the receive153 and/or transmit absolute delays does not force the controller to154 generate more interrupts than what the Interrupt Throttle Rate155 allows.156 157CAUTION:158 If you are using the Intel(R) PRO/1000 CT Network Connection159 (controller 82547), setting InterruptThrottleRate to a value160 greater than 75,000, may hang (stop transmitting) adapters161 under certain network conditions. If this occurs a NETDEV162 WATCHDOG message is logged in the system event log. In163 addition, the controller is automatically reset, restoring164 the network connection. To eliminate the potential for the165 hang, ensure that InterruptThrottleRate is set no greater166 than 75,000 and is not set to 0.167 168NOTE:169 When e1000 is loaded with default settings and multiple adapters170 are in use simultaneously, the CPU utilization may increase non-171 linearly. In order to limit the CPU utilization without impacting172 the overall throughput, we recommend that you load the driver as173 follows::174 175 modprobe e1000 InterruptThrottleRate=3000,3000,3000176 177 This sets the InterruptThrottleRate to 3000 interrupts/sec for178 the first, second, and third instances of the driver. The range179 of 2000 to 3000 interrupts per second works on a majority of180 systems and is a good starting point, but the optimal value will181 be platform-specific. If CPU utilization is not a concern, use182 RX_POLLING (NAPI) and default driver settings.183 184RxDescriptors185-------------186 187:Valid Range:188 - 48-256 for 82542 and 82543-based adapters189 - 48-4096 for all other supported adapters190:Default Value: 256191 192This value specifies the number of receive buffer descriptors allocated193by the driver. Increasing this value allows the driver to buffer more194incoming packets, at the expense of increased system memory utilization.195 196Each descriptor is 16 bytes. A receive buffer is also allocated for each197descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending198on the MTU setting. The maximum MTU size is 16110.199 200NOTE:201 MTU designates the frame size. It only needs to be set for Jumbo202 Frames. Depending on the available system resources, the request203 for a higher number of receive descriptors may be denied. In this204 case, use a lower number.205 206RxIntDelay207----------208 209:Valid Range: 0-65535 (0=off)210:Default Value: 0211 212This value delays the generation of receive interrupts in units of 1.024213microseconds. Receive interrupt reduction can improve CPU efficiency if214properly tuned for specific network traffic. Increasing this value adds215extra latency to frame reception and can end up decreasing the throughput216of TCP traffic. If the system is reporting dropped receives, this value217may be set too high, causing the driver to run out of available receive218descriptors.219 220CAUTION:221 When setting RxIntDelay to a value other than 0, adapters may222 hang (stop transmitting) under certain network conditions. If223 this occurs a NETDEV WATCHDOG message is logged in the system224 event log. In addition, the controller is automatically reset,225 restoring the network connection. To eliminate the potential226 for the hang ensure that RxIntDelay is set to 0.227 228RxAbsIntDelay229-------------230 231(This parameter is supported only on 82540, 82545 and later adapters.)232 233:Valid Range: 0-65535 (0=off)234:Default Value: 128235 236This value, in units of 1.024 microseconds, limits the delay in which a237receive interrupt is generated. Useful only if RxIntDelay is non-zero,238this value ensures that an interrupt is generated after the initial239packet is received within the set amount of time. Proper tuning,240along with RxIntDelay, may improve traffic throughput in specific network241conditions.242 243Speed244-----245 246(This parameter is supported only on adapters with copper connections.)247 248:Valid Settings: 0, 10, 100, 1000249:Default Value: 0 (auto-negotiate at all supported speeds)250 251Speed forces the line speed to the specified value in megabits per second252(Mbps). If this parameter is not specified or is set to 0 and the link253partner is set to auto-negotiate, the board will auto-detect the correct254speed. Duplex should also be set when Speed is set to either 10 or 100.255 256TxDescriptors257-------------258 259:Valid Range:260 - 48-256 for 82542 and 82543-based adapters261 - 48-4096 for all other supported adapters262:Default Value: 256263 264This value is the number of transmit descriptors allocated by the driver.265Increasing this value allows the driver to queue more transmits. Each266descriptor is 16 bytes.267 268NOTE:269 Depending on the available system resources, the request for a270 higher number of transmit descriptors may be denied. In this case,271 use a lower number.272 273TxIntDelay274----------275 276:Valid Range: 0-65535 (0=off)277:Default Value: 8278 279This value delays the generation of transmit interrupts in units of2801.024 microseconds. Transmit interrupt reduction can improve CPU281efficiency if properly tuned for specific network traffic. If the282system is reporting dropped transmits, this value may be set too high283causing the driver to run out of available transmit descriptors.284 285TxAbsIntDelay286-------------287 288(This parameter is supported only on 82540, 82545 and later adapters.)289 290:Valid Range: 0-65535 (0=off)291:Default Value: 32292 293This value, in units of 1.024 microseconds, limits the delay in which a294transmit interrupt is generated. Useful only if TxIntDelay is non-zero,295this value ensures that an interrupt is generated after the initial296packet is sent on the wire within the set amount of time. Proper tuning,297along with TxIntDelay, may improve traffic throughput in specific298network conditions.299 300XsumRX301------302 303(This parameter is NOT supported on the 82542-based adapter.)304 305:Valid Range: 0-1306:Default Value: 1307 308A value of '1' indicates that the driver should enable IP checksum309offload for received packets (both UDP and TCP) to the adapter hardware.310 311Copybreak312---------313 314:Valid Range: 0-xxxxxxx (0=off)315:Default Value: 256316:Usage: modprobe e1000.ko copybreak=128317 318Driver copies all packets below or equaling this size to a fresh RX319buffer before handing it up the stack.320 321This parameter is different than other parameters, in that it is a322single (not 1,1,1 etc.) parameter applied to all driver instances and323it is also available during runtime at324/sys/module/e1000/parameters/copybreak325 326SmartPowerDownEnable327--------------------328 329:Valid Range: 0-1330:Default Value: 0 (disabled)331 332Allows PHY to turn off in lower power states. The user can turn off333this parameter in supported chipsets.334 335Speed and Duplex Configuration336==============================337 338Three keywords are used to control the speed and duplex configuration.339These keywords are Speed, Duplex, and AutoNeg.340 341If the board uses a fiber interface, these keywords are ignored, and the342fiber interface board only links at 1000 Mbps full-duplex.343 344For copper-based boards, the keywords interact as follows:345 346- The default operation is auto-negotiate. The board advertises all347 supported speed and duplex combinations, and it links at the highest348 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 Mbps351 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. Partner355 SHOULD also be forced.356 357The AutoNeg parameter is used when more control is required over the358auto-negotiation process. It should be used when you wish to control which359speed and duplex combinations are advertised during the auto-negotiation360process.361 362The parameter may be specified as either a decimal or hexadecimal value as363determined by the bitmap below.364 365============== ====== ====== ======= ======= ====== ====== ======= ======366Bit position 7 6 5 4 3 2 1 0367Decimal Value 128 64 32 16 8 4 2 1368Hex value 80 40 20 10 8 4 2 1369Speed (Mbps) N/A N/A 1000 N/A 100 100 10 10370Duplex Full Full Half Full Half371============== ====== ====== ======= ======= ====== ====== ======= ======372 373Some 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 100381 Half)382 modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)383 modprobe e1000 AutoNeg=32 (Same as above)384 385Note that when this parameter is used, Speed and Duplex must not be specified.386 387If the link partner is forced to a specific speed and duplex, then this388parameter should not be used. Instead, use the Speed and Duplex parameters389previously mentioned to force the adapter to the same speed and duplex.390 391Additional Configurations392=========================393 394Jumbo Frames395------------396 397 Jumbo Frames support is enabled by changing the MTU to a value larger than398 the default of 1500. Use the ifconfig command to increase the MTU size.399 For example::400 401 ifconfig eth<x> mtu 9000 up402 403 This setting is not saved across reboots. It can be made permanent if404 you add::405 406 MTU=9000407 408 to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>. This example409 applies to the Red Hat distributions; other distributions may store this410 setting in a different location.411 412Notes:413 Degradation in throughput performance may be observed in some Jumbo frames414 environments. If this is observed, increasing the application's socket buffer415 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 coincides420 with the maximum Jumbo Frames size of 16128.421 422 - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in423 poor performance or loss of link.424 425 - Adapters based on the Intel(R) 82542 and 82573V/E controller do not426 support Jumbo Frames. These correspond to the following product names::427 428 Intel(R) PRO/1000 Gigabit Server Adapter429 Intel(R) PRO/1000 PM Network Connection430 431ethtool432-------433 434 The driver utilizes the ethtool interface for driver configuration and435 diagnostics, as well as displaying statistical information. The ethtool436 version 1.6 or later is required for this functionality.437 438 The latest release of ethtool can be found from439 https://www.kernel.org/pub/software/network/ethtool/440 441Enabling 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 be448 loaded when shutting down or rebooting the system.449 450Support451=======452 453For general information, go to the Intel support website at:454http://support.intel.com455 456If an issue is identified with the released source code on the supported457kernel with a supported adapter, email the specific information related458to the issue to intel-wired-lan@lists.osuosl.org.459