Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters =============================================================== November 17, 2004 Contents ======== - In This Release - Identifying Your Adapter - Command Line Parameters - Speed and Duplex Configuration - Additional Configurations - Known Issues - Support In This Release =============== This file describes the Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters, version 5.x.x. For questions related to hardware requirements, refer to the documentation supplied with your Intel PRO/1000 adapter. All hardware requirements listed apply to use with Linux. Native VLANs are now available with supported kernels. Identifying Your Adapter ======================== For more information on how to identify your adapter, go to the Adapter & Driver ID Guide at: http://support.intel.com/support/network/adapter/pro100/21397.htm For the latest Intel network drivers for Linux, refer to the following website. In the search field, enter your adapter name or type, or use the networking link on the left to search for your adapter: http://downloadfinder.intel.com/scripts-df/support_intel.asp Command Line Parameters ======================= If the driver is built as a module, the following optional parameters are used by entering them on the command line with the modprobe or insmod command using this syntax: modprobe e1000 [<option>=<VAL1>,<VAL2>,...] insmod e1000 [<option>=<VAL1>,<VAL2>,...] For example, with two PRO/1000 PCI adapters, entering: insmod e1000 TxDescriptors=80,128 loads the e1000 driver with 80 TX descriptors for the first adapter and 128 TX descriptors for the second adapter. The default value for each parameter is generally the recommended setting, unless otherwise noted. Also, if the driver is statically built into the kernel, the driver is loaded with the default values for all the parameters. Ethtool can be used to change some of the parameters at runtime. NOTES: For more information about the AutoNeg, Duplex, and Speed parameters, see the "Speed and Duplex Configuration" section in this document. For more information about the InterruptThrottleRate, RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay parameters, see the application note at: http://www.intel.com/design/network/applnots/ap450.htm A descriptor describes a data buffer and attributes related to the data buffer. This information is accessed by the hardware. AutoNeg (adapters using copper connections only) Valid Range: 0x01-0x0F, 0x20-0x2F Default Value: 0x2F This parameter is a bit mask that specifies which speed and duplex settings the board advertises. When this parameter is used, the Speed and Duplex parameters must not be specified. NOTE: Refer to the Speed and Duplex section of this readme for more information on the AutoNeg parameter. Duplex (adapters using copper connections only) Valid Range: 0-2 (0=auto-negotiate, 1=half, 2=full) Default Value: 0 Defines the direction in which data is allowed to flow. Can be either one or two-directional. If both Duplex and the link partner are set to auto- negotiate, the board auto-detects the correct duplex. If the link partner is forced (either full or half), Duplex defaults to half-duplex. FlowControl Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) Default: Read flow control settings from the EEPROM This parameter controls the automatic generation(Tx) and response(Rx) to Ethernet PAUSE frames. InterruptThrottleRate Valid Range: 100-100000 (0=off, 1=dynamic) Default Value: 8000 This value represents the maximum number of interrupts per second the controller generates. InterruptThrottleRate is another setting used in interrupt moderation. Dynamic mode uses a heuristic algorithm to adjust InterruptThrottleRate based on the current traffic load. Un-supported Adapters: InterruptThrottleRate is NOT supported by 82542, 82543 or 82544-based adapters. NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and RxAbsIntDelay parameters. In other words, minimizing the receive and/or transmit absolute delays does not force the controller to generate more interrupts than what the Interrupt Throttle Rate allows. CAUTION: If you are using the Intel PRO/1000 CT Network Connection (controller 82547), setting InterruptThrottleRate to a value greater than 75,000, may hang (stop transmitting) adapters under certain network conditions. If this occurs a NETDEV WATCHDOG message is logged in the system event log. In addition, the controller is automatically reset, restoring the network connection. To eliminate the potential for the hang, ensure that InterruptThrottleRate is set no greater than 75,000 and is not set to 0. NOTE: When e1000 is loaded with default settings and multiple adapters are in use simultaneously, the CPU utilization may increase non-linearly. In order to limit the CPU utilization without impacting the overall throughput, we recommend that you load the driver as follows: insmod e1000.o InterruptThrottleRate=3000,3000,3000 This sets the InterruptThrottleRate to 3000 interrupts/sec for the first, second, and third instances of the driver. The range of 2000 to 3000 interrupts per second works on a majority of systems and is a good starting point, but the optimal value will be platform-specific. If CPU utilization is not a concern, use RX_POLLING (NAPI) and default driver settings. RxDescriptors Valid Range: 80-256 for 82542 and 82543-based adapters 80-4096 for all other supported adapters Default Value: 256 This value is the number of receive descriptors allocated by the driver. Increasing this value allows the driver to buffer more incoming packets. Each descriptor is 16 bytes. A receive buffer is allocated for each descriptor and can either be 2048 or 4096 bytes long, depending on the MTU setting. An incoming packet can span one or more receive descriptors. The maximum MTU size is 16110. NOTE: MTU designates the frame size. It only needs to be set for Jumbo Frames. NOTE: Depending on the available system resources, the request for a higher number of receive descriptors may be denied. In this case, use a lower number. RxIntDelay Valid Range: 0-65535 (0=off) Default Value: 0 This value delays the generation of receive interrupts in units of 1.024 microseconds. Receive interrupt reduction can improve CPU efficiency if properly tuned for specific network traffic. Increasing this value adds extra latency to frame reception and can end up decreasing the throughput of TCP traffic. If the system is reporting dropped receives, this value may be set too high, causing the driver to run out of available receive descriptors. CAUTION: When setting RxIntDelay to a value other than 0, adapters may hang (stop transmitting) under certain network conditions. If this occurs a NETDEV WATCHDOG message is logged in the system event log. In addition, the controller is automatically reset, restoring the network connection. To eliminate the potential for the hang ensure that RxIntDelay is set to 0. RxAbsIntDelay (82540, 82545 and later adapters only) Valid Range: 0-65535 (0=off) Default Value: 128 This value, in units of 1.024 microseconds, limits the delay in which a receive interrupt is generated. Useful only if RxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is received within the set amount of time. Proper tuning, along with RxIntDelay, may improve traffic throughput in specific network conditions. Speed (adapters using copper connections only) Valid Settings: 0, 10, 100, 1000 Default Value: 0 (auto-negotiate at all supported speeds) Speed forces the line speed to the specified value in megabits per second (Mbps). If this parameter is not specified or is set to 0 and the link partner is set to auto-negotiate, the board will auto-detect the correct speed. Duplex should also be set when Speed is set to either 10 or 100. TxDescriptors Valid Range: 80-256 for 82542 and 82543-based adapters 80-4096 for all other supported adapters Default Value: 256 This value is the number of transmit descriptors allocated by the driver. Increasing this value allows the driver to queue more transmits. Each descriptor is 16 bytes. NOTE: Depending on the available system resources, the request for a higher number of transmit descriptors may be denied. In this case, use a lower number. TxIntDelay Valid Range: 0-65535 (0=off) Default Value: 64 This value delays the generation of transmit interrupts in units of 1.024 microseconds. Transmit interrupt reduction can improve CPU efficiency if properly tuned for specific network traffic. If the system is reporting dropped transmits, this value may be set too high causing the driver to run out of available transmit descriptors. TxAbsIntDelay (82540, 82545 and later adapters only) Valid Range: 0-65535 (0=off) Default Value: 64 This value, in units of 1.024 microseconds, limits the delay in which a transmit interrupt is generated. Useful only if TxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is sent on the wire within the set amount of time. Proper tuning, along with TxIntDelay, may improve traffic throughput in specific network conditions. XsumRX (not available on the 82542-based adapter) Valid Range: 0-1 Default Value: 1 A value of '1' indicates that the driver should enable IP checksum offload for received packets (both UDP and TCP) to the adapter hardware. Speed and Duplex Configuration ============================== Three keywords are used to control the speed and duplex configuration. These keywords are Speed, Duplex, and AutoNeg. If the board uses a fiber interface, these keywords are ignored, and the fiber interface board only links at 1000 Mbps full-duplex. For copper-based boards, the keywords interact as follows: The default operation is auto-negotiate. The board advertises all supported speed and duplex combinations, and it links at the highest common speed and duplex mode IF the link partner is set to auto-negotiate. If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps is advertised (The 1000BaseT spec requires auto-negotiation.) If Speed = 10 or 100, then both Speed and Duplex should be set. Auto- negotiation is disabled, and the AutoNeg parameter is ignored. Partner SHOULD also be forced. The AutoNeg parameter is used when more control is required over the auto- negotiation process. When this parameter is used, Speed and Duplex parameters must not be specified. The following table describes supported values for the AutoNeg parameter: Speed (Mbps) 1000 100 100 10 10 Duplex Full Full Half Full Half Value (in base 16) 0x20 0x08 0x04 0x02 0x01 Example: insmod e1000 AutoNeg=0x03, loads e1000 and specifies (10 full duplex, 10 half duplex) for negotiation with the peer. Note that setting AutoNeg does not guarantee that the board will link at the highest specified speed or duplex mode, but the board will link at the highest possible speed/duplex of the link partner IF the link partner is also set to auto-negotiate. If the link partner is forced speed/duplex, the adapter MUST be forced to the same speed/duplex. Additional Configurations ========================= Configuring the Driver on Different Distributions ------------------------------------------------- Configuring a network driver to load properly when the system is started is distribution dependent. Typically, the configuration process involves adding an alias line to /etc/modules.conf as well as editing other system startup scripts and/or configuration files. Many popular Linux distributions ship with tools to make these changes for you. To learn the proper way to configure a network device for your system, refer to your distribution documentation. If during this process you are asked for the driver or module name, the name for the Linux Base Driver for the Intel PRO/1000 Family of Adapters is e1000. As an example, if you install the e1000 driver for two PRO/1000 adapters (eth0 and eth1) and set the speed and duplex to 10full and 100half, add the following to modules.conf: alias eth0 e1000 alias eth1 e1000 options e1000 Speed=10,100 Duplex=2,1 Viewing Link Messages --------------------- Link messages will not be displayed to the console if the distribution is restricting system messages. In order to see network driver link messages on your console, set dmesg to eight by entering the following: dmesg -n 8 NOTE: This setting is not saved across reboots. Jumbo Frames ------------ The driver supports Jumbo Frames for all adapters except 82542-based adapters. Jumbo Frames support is enabled by changing the MTU to a value larger than the default of 1500. Use the ifconfig command to increase the MTU size. For example: ifconfig ethx mtu 9000 up The maximum MTU setting for Jumbo Frames is 16110. This value coincides with the maximum Jumbo Frames size of 16128. NOTE: Jumbo Frames are supported at 1000 Mbps only. Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or loss of link. NOTE: MTU designates the frame size. To enable Jumbo Frames, increase the MTU size on the interface beyond 1500. Ethtool ------- The driver utilizes the ethtool interface for driver configuration and diagnostics, as well as displaying statistical information. Ethtool version 1.6 or later is required for this functionality. The latest release of ethtool can be found from http://sf.net/projects/gkernel. NOTE: Ethtool 1.6 only supports a limited set of ethtool options. Support for a more complete ethtool feature set can be enabled by upgrading ethtool to ethtool-1.8.1. Enabling Wake on LAN* (WoL) --------------------------- WoL is configured through the Ethtool* utility. Ethtool is included with all versions of Red Hat after Red Hat 7.2. For other Linux distributions, download and install Ethtool from the following website: http://sourceforge.net/projects/gkernel. For instructions on enabling WoL with Ethtool, refer to the website listed above. WoL will be enabled on the system during the next shut down or reboot. For this driver version, in order to enable WoL, the e1000 driver must be loaded when shutting down or rebooting the system. NAPI ---- NAPI (Rx polling mode) is supported in the e1000 driver. NAPI is enabled or disabled based on the configuration of the kernel. See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI. Known Issues ============ Jumbo Frames System Requirement ------------------------------- Memory allocation failures have been observed on Linux systems with 64 MB of RAM or less that are running Jumbo Frames. If you are using Jumbo Frames, your system may require more than the advertised minimum requirement of 64 MB of system memory. Support ======= For general information, go to the Intel support website at: http://support.intel.com If an issue is identified with the released source code on the supported kernel with a supported adapter, email the specific information related to the issue to linux.nics@intel.com. License ======= This software program is released under the terms of a license agreement between you ('Licensee') and Intel. Do not use or load this software or any associated materials (collectively, the 'Software') until you have carefully read the full terms and conditions of the LICENSE located in this software package. By loading or using the Software, you agree to the terms of this Agreement. If you do not agree with the terms of this Agreement, do not install or use the Software. * Other names and brands may be claimed as the property of others.