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diff --git a/Documentation/networking/e1000e.txt b/Documentation/networking/e1000e.txt new file mode 100644 index 000000000..12089547b --- /dev/null +++ b/Documentation/networking/e1000e.txt @@ -0,0 +1,312 @@ +Linux* Driver for Intel(R) Ethernet Network Connection +====================================================== + +Intel Gigabit Linux driver. +Copyright(c) 1999 - 2013 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Additional Configurations +- Support + +Identifying Your Adapter +======================== + +The e1000e driver supports all PCI Express Intel(R) Gigabit Network +Connections, except those that are 82575, 82576 and 82580-based*. + +* NOTE: The Intel(R) PRO/1000 P Dual Port Server Adapter is supported by + the e1000 driver, not the e1000e driver due to the 82546 part being used + behind a PCI Express bridge. + +For more information on how to identify your adapter, go to the Adapter & +Driver ID Guide at: + + http://support.intel.com/support/go/network/adapter/idguide.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://support.intel.com/support/go/network/adapter/home.htm + +Command Line Parameters +======================= + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +NOTES: 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 + +InterruptThrottleRate +--------------------- +Valid Range: 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, + 4=simplified balancing) +Default Value: 3 + +The driver can limit the amount of interrupts per second that the adapter +will generate for incoming packets. It does this by writing a value to the +adapter that is based on the maximum amount of interrupts that the adapter +will generate per second. + +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. + +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. + +For situations where low latency is vital such as cluster or +grid computing, the algorithm can reduce latency even more when +InterruptThrottleRate is set to mode 1. In this mode, which operates +the same as mode 3, the InterruptThrottleRate will be increased stepwise to +70000 for traffic in class "Lowest latency". + +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. + +Setting InterruptThrottleRate to 0 turns off any interrupt moderation +and may improve small packet latency, but is generally not suitable +for bulk throughput traffic. + +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. + +NOTE: When e1000e 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: + + modprobe e1000e 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. + +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. 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. + +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. 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. + +Copybreak +--------- +Valid Range: 0-xxxxxxx (0=off) +Default Value: 256 + +Driver copies all packets below or equaling this size to a fresh RX +buffer before handing it up the stack. + +This parameter is different than other parameters, in that 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 + +SmartPowerDownEnable +-------------------- +Valid Range: 0-1 +Default Value: 0 (disabled) + +Allows PHY to turn off in lower power states. The user can set 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 (0=legacy, 1=MSI, 2=MSI-X) +Default Value: 2 + +Allows changing the interrupt mode at module load time, without requiring a +recompile. If the driver load fails to enable a specific interrupt mode, the +driver will try other interrupt modes, from least to most compatible. The +interrupt order is MSI-X, MSI, Legacy. If specifying MSI (IntMode=1) +interrupts, only MSI and Legacy will be attempted. + +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 + +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. + +Additional Configurations +========================= + + Jumbo Frames + ------------ + 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 eth<x> mtu 9000 up + + This setting is not saved across reboots. + + Notes: + + - The maximum MTU setting for Jumbo Frames is 9216. This value coincides + with the maximum Jumbo Frames size of 9234 bytes. + + - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in + poor performance or loss of link. + + - Some adapters limit Jumbo Frames sized packets to a maximum of + 4096 bytes and some adapters do not support Jumbo Frames. + + - 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. We + strongly recommend downloading the latest version of ethtool at: + + https://kernel.org/pub/software/network/ethtool/ + + NOTE: When validating enable/disable tests on some parts (82578, for example) + you need to add a few seconds between tests when working with ethtool. + + Speed and Duplex + ---------------- + Speed and Duplex are configured through the ethtool* utility. For + instructions, refer to the ethtool man page. + + Enabling Wake on LAN* (WoL) + --------------------------- + WoL is configured through the ethtool* utility. For instructions on + enabling WoL with ethtool, refer to the ethtool man page. + + 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 when shutting down or rebooting the system. + + In most cases Wake On LAN is only supported on port A for multiple port + adapters. To verify if a port supports Wake on Lan run ethtool eth<X>. + +Support +======= + +For general information, go to the Intel support website at: + + www.intel.com/support/ + +or the Intel Wired Networking project hosted by Sourceforge at: + + http://sourceforge.net/projects/e1000 + +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 e1000-devel@lists.sf.net |