| .. 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. |