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diff --git a/Documentation/networking/e1000e.rst b/Documentation/networking/e1000e.rst new file mode 100644 index 000000000000..33554e5416c5 --- /dev/null +++ b/Documentation/networking/e1000e.rst @@ -0,0 +1,382 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +Linux* Driver for Intel(R) Ethernet Network Connection +====================================================== + +Intel Gigabit Linux driver. +Copyright(c) 2008-2018 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Additional Configurations +- Support + + +Identifying Your Adapter +======================== +For information on how to identify your adapter, and for the latest Intel +network drivers, refer to the Intel Support website: +https://www.intel.com/support + + +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 command using this +syntax:: + + modprobe e1000e [<option>=<VAL1>,<VAL2>,...] + +There needs to be a <VAL#> for each network port in the system supported by +this driver. The values will be applied to each instance, in function order. +For example:: + + modprobe e1000e InterruptThrottleRate=16000,16000 + +In this case, there are two network ports supported by e1000e in the system. +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +NOTE: A descriptor describes a data buffer and attributes related to the data +buffer. This information is accessed by the hardware. + +InterruptThrottleRate +--------------------- +:Valid Range: 0,1,3,4,100-100000 +:Default Value: 3 + +Interrupt Throttle Rate controls the number of interrupts each interrupt +vector can generate per second. Increasing ITR lowers latency at the cost of +increased CPU utilization, though it may help throughput in some circumstances. + +Setting InterruptThrottleRate to a value greater or equal to 100 +will program the adapter to send out a maximum of that many interrupts +per second, even if more packets have come in. This reduces interrupt +load on the system and can lower CPU utilization under heavy load, +but will increase latency as packets are not processed as quickly. + +The default behaviour of the driver previously assumed a static +InterruptThrottleRate value of 8000, providing a good fallback value for +all traffic types, but lacking in small packet performance and latency. +The hardware can handle many more small packets per second however, and +for this reason an adaptive interrupt moderation algorithm was implemented. + +The driver has two adaptive modes (setting 1 or 3) in which +it dynamically adjusts the InterruptThrottleRate value based on the traffic +that it receives. After determining the type of incoming traffic in the last +timeframe, it will adjust the InterruptThrottleRate to an appropriate value +for that traffic. + +The algorithm classifies the incoming traffic every interval into +classes. Once the class is determined, the InterruptThrottleRate value is +adjusted to suit that traffic type the best. There are three classes defined: +"Bulk traffic", for large amounts of packets of normal size; "Low latency", +for small amounts of traffic and/or a significant percentage of small +packets; and "Lowest latency", for almost completely small packets or +minimal traffic. + + - 0: Off + Turns off any interrupt moderation and may improve small packet latency. + However, this is generally not suitable for bulk throughput traffic due + to the increased CPU utilization of the higher interrupt rate. + - 1: Dynamic mode + This mode attempts to moderate interrupts per vector while maintaining + very low latency. This can sometimes cause extra CPU utilization. If + planning on deploying e1000e in a latency sensitive environment, this + parameter should be considered. + - 3: Dynamic Conservative mode (default) + In dynamic conservative mode, the InterruptThrottleRate value is set to + 4000 for traffic that falls in class "Bulk traffic". If traffic falls in + the "Low latency" or "Lowest latency" class, the InterruptThrottleRate is + increased stepwise to 20000. This default mode is suitable for most + applications. + - 4: Simplified Balancing mode + In simplified mode the interrupt rate is based on the ratio of TX and + RX traffic. If the bytes per second rate is approximately equal, the + interrupt rate will drop as low as 2000 interrupts per second. If the + traffic is mostly transmit or mostly receive, the interrupt rate could + be as high as 8000. + - 100-100000: + Setting InterruptThrottleRate to a value greater or equal to 100 + will program the adapter to send at most that many interrupts per second, + even if more packets have come in. This reduces interrupt load on the + system and can lower CPU utilization under heavy load, but will increase + latency as packets are not processed as quickly. + +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. + +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 +------------- +:Valid Range: 0-65535 (0=off) +:Default Value: 8 + +This value, in units of 1.024 microseconds, limits the delay in which a +receive interrupt is generated. This value ensures that an interrupt is +generated after the initial packet is received within the set amount of time, +which is useful only if RxIntDelay is non-zero. Proper tuning, along with +RxIntDelay, may improve traffic throughput in specific network conditions. + +TxIntDelay +---------- +:Valid Range: 0-65535 (0=off) +:Default Value: 8 + +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 +------------- +:Valid Range: 0-65535 (0=off) +:Default Value: 32 + +This value, in units of 1.024 microseconds, limits the delay in which a +transmit interrupt is generated. It is useful only if TxIntDelay is non-zero. +It 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. + +copybreak +--------- +:Valid Range: 0-xxxxxxx (0=off) +:Default Value: 256 + +The driver copies all packets below or equaling this size to a fresh receive +buffer before handing it up the stack. +This parameter differs from other parameters because it is a single (not 1,1,1 +etc.) parameter applied to all driver instances and it is also available +during runtime at /sys/module/e1000e/parameters/copybreak. + +To use copybreak, type:: + + modprobe e1000e.ko copybreak=128 + +SmartPowerDownEnable +-------------------- +:Valid Range: 0,1 +:Default Value: 0 (disabled) + +Allows the PHY to turn off in lower power states. The user can turn off this +parameter in supported chipsets. + +KumeranLockLoss +--------------- +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +This workaround skips resetting the PHY at shutdown for the initial silicon +releases of ICH8 systems. + +IntMode +------- +:Valid Range: 0-2 +:Default Value: 0 + + +-------+----------------+ + | Value | Interrupt Mode | + +=======+================+ + | 0 | Legacy | + +-------+----------------+ + | 1 | MSI | + +-------+----------------+ + | 2 | MSI-X | + +-------+----------------+ + +IntMode allows load time control over the type of interrupt registered for by +the driver. MSI-X is required for multiple queue support, and some kernels and +combinations of kernel .config options will force a lower level of interrupt +support. + +This command will show different values for each type of interrupt:: + + cat /proc/interrupts + +CrcStripping +------------ +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +Strip the CRC from received packets before sending up the network stack. If +you have a machine with a BMC enabled but cannot receive IPMI traffic after +loading or enabling the driver, try disabling this feature. + +WriteProtectNVM +--------------- +:Valid Range: 0,1 +:Default Value: 1 (enabled) + +If set to 1, configure the hardware to ignore all write/erase cycles to the +GbE region in the ICHx NVM (in order to prevent accidental corruption of the +NVM). This feature can be disabled by setting the parameter to 0 during initial +driver load. + +NOTE: The machine must be power cycled (full off/on) when enabling NVM writes +via setting the parameter to zero. Once the NVM has been locked (via the +parameter at 1 when the driver loads) it cannot be unlocked except via power +cycle. + +Debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level of debug messages displayed in the system logs. + + +Additional Features and Configurations +====================================== + +Jumbo Frames +------------ +Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) +to a value larger than the default value of 1500. + +Use the ifconfig command to increase the MTU size. For example, enter the +following where <x> is the interface number:: + + ifconfig eth<x> mtu 9000 up + +Alternatively, you can use the ip command as follows:: + + ip link set mtu 9000 dev eth<x> + ip link set up dev eth<x> + +This setting is not saved across reboots. The setting change can be made +permanent by adding 'MTU=9000' to the file: + +- For RHEL: /etc/sysconfig/network-scripts/ifcfg-eth<x> +- For SLES: /etc/sysconfig/network/<config_file> + +NOTE: The maximum MTU setting for Jumbo Frames is 8996. This value coincides +with the maximum Jumbo Frames size of 9018 bytes. + +NOTE: Using Jumbo frames at 10 or 100 Mbps is not supported and may result in +poor performance or loss of link. + +NOTE: The following adapters limit Jumbo Frames sized packets to a maximum of +4088 bytes: + + - Intel(R) 82578DM Gigabit Network Connection + - Intel(R) 82577LM Gigabit Network Connection + +The following adapters do not support Jumbo Frames: + + - Intel(R) PRO/1000 Gigabit Server Adapter + - Intel(R) PRO/1000 PM Network Connection + - Intel(R) 82562G 10/100 Network Connection + - Intel(R) 82562G-2 10/100 Network Connection + - Intel(R) 82562GT 10/100 Network Connection + - Intel(R) 82562GT-2 10/100 Network Connection + - Intel(R) 82562V 10/100 Network Connection + - Intel(R) 82562V-2 10/100 Network Connection + - Intel(R) 82566DC Gigabit Network Connection + - Intel(R) 82566DC-2 Gigabit Network Connection + - Intel(R) 82566DM Gigabit Network Connection + - Intel(R) 82566MC Gigabit Network Connection + - Intel(R) 82566MM Gigabit Network Connection + - Intel(R) 82567V-3 Gigabit Network Connection + - Intel(R) 82577LC Gigabit Network Connection + - Intel(R) 82578DC Gigabit Network Connection + +NOTE: Jumbo Frames cannot be configured on an 82579-based Network device if +MACSec is enabled on the system. + + +ethtool +------- +The driver utilizes the ethtool interface for driver configuration and +diagnostics, as well as displaying statistical information. The latest ethtool +version is required for this functionality. Download it at: + +https://www.kernel.org/pub/software/network/ethtool/ + +NOTE: When validating enable/disable tests on some parts (for example, 82578), +it is necessary to add a few seconds between tests when working with ethtool. + + +Speed and Duplex Configuration +------------------------------ +In addressing speed and duplex configuration issues, you need to distinguish +between copper-based adapters and fiber-based adapters. + +In the default mode, an Intel(R) Ethernet Network Adapter using copper +connections will attempt to auto-negotiate with its link partner to determine +the best setting. If the adapter cannot establish link with the link partner +using auto-negotiation, you may need to manually configure the adapter and link +partner to identical settings to establish link and pass packets. This should +only be needed when attempting to link with an older switch that does not +support auto-negotiation or one that has been forced to a specific speed or +duplex mode. Your link partner must match the setting you choose. 1 Gbps speeds +and higher cannot be forced. Use the autonegotiation advertising setting to +manually set devices for 1 Gbps and higher. + +Speed, duplex, and autonegotiation advertising are configured through the +ethtool* utility. + +Caution: Only experienced network administrators should force speed and duplex +or change autonegotiation advertising manually. The settings at the switch must +always match the adapter settings. Adapter performance may suffer or your +adapter may not operate if you configure the adapter differently from your +switch. + +An Intel(R) Ethernet Network Adapter using fiber-based connections, however, +will not attempt to auto-negotiate with its link partner since those adapters +operate only in full duplex and only at their native speed. + + +Enabling Wake on LAN* (WoL) +--------------------------- +WoL is configured through the ethtool* utility. + +WoL will be enabled on the system during the next shut down or reboot. For +this driver version, in order to enable WoL, the e1000e driver must be loaded +prior to shutting down or suspending the system. + +NOTE: Wake on LAN is only supported on port A for the following devices: +- Intel(R) PRO/1000 PT Dual Port Network Connection +- Intel(R) PRO/1000 PT Dual Port Server Connection +- Intel(R) PRO/1000 PT Dual Port Server Adapter +- Intel(R) PRO/1000 PF Dual Port Server Adapter +- Intel(R) PRO/1000 PT Quad Port Server Adapter +- Intel(R) Gigabit PT Quad Port Server ExpressModule + + +Support +======= +For general information, go to the Intel support website at: + +https://www.intel.com/support/ + +or the Intel Wired Networking project hosted by Sourceforge at: + +https://sourceforge.net/projects/e1000 + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the issue +to e1000-devel@lists.sf.net. |
