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diff --git a/kernel/Documentation/networking/e1000.txt b/kernel/Documentation/networking/e1000.txt new file mode 100644 index 000000000..437b2099c --- /dev/null +++ b/kernel/Documentation/networking/e1000.txt @@ -0,0 +1,461 @@ +Linux* Base Driver for Intel(R) Ethernet Network Connection +=========================================================== + +Intel Gigabit Linux driver. +Copyright(c) 1999 - 2013 Intel Corporation. + +Contents +======== + +- Identifying Your Adapter +- Command Line Parameters +- Speed and Duplex Configuration +- Additional Configurations +- Support + +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/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 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 + +AutoNeg +------- +(Supported only on adapters with copper connections) +Valid Range: 0x01-0x0F, 0x20-0x2F +Default Value: 0x2F + +This parameter is a bit-mask that specifies the speed and duplex settings +advertised by the adapter. 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 +------ +(Supported only on adapters with copper connections) +Valid Range: 0-2 (0=auto-negotiate, 1=half, 2=full) +Default Value: 0 + +This 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 Value: Reads flow control settings from the EEPROM + +This parameter controls the automatic generation(Tx) and response(Rx) +to Ethernet PAUSE frames. + +InterruptThrottleRate +--------------------- +(not supported on Intel(R) 82542, 82543 or 82544-based adapters) +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. + +Since 7.3.x, 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. + +CAUTION: If you are using the Intel(R) 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: + + modprobe e1000 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 specifies the number of receive buffer descriptors allocated +by the driver. Increasing this value allows the driver to buffer more +incoming packets, at the expense of increased system memory utilization. + +Each descriptor is 16 bytes. A receive buffer is also allocated for each +descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending +on the MTU setting. The maximum MTU size is 16110. + +NOTE: MTU designates the frame size. It only needs to be set for Jumbo + Frames. 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 +------------- +(This parameter is supported only on 82540, 82545 and later adapters.) +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 +----- +(This parameter is supported only on adapters with copper connections.) +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. + +TxDescriptorStep +---------------- +Valid Range: 1 (use every Tx Descriptor) + 4 (use every 4th Tx Descriptor) + +Default Value: 1 (use every Tx Descriptor) + +On certain non-Intel architectures, it has been observed that intense TX +traffic bursts of short packets may result in an improper descriptor +writeback. If this occurs, the driver will report a "TX Timeout" and reset +the adapter, after which the transmit flow will restart, though data may +have stalled for as much as 10 seconds before it resumes. + +The improper writeback does not occur on the first descriptor in a system +memory cache-line, which is typically 32 bytes, or 4 descriptors long. + +Setting TxDescriptorStep to a value of 4 will ensure that all TX descriptors +are aligned to the start of a system memory cache line, and so this problem +will not occur. + +NOTES: Setting TxDescriptorStep to 4 effectively reduces the number of + TxDescriptors available for transmits to 1/4 of the normal allocation. + This has a possible negative performance impact, which may be + compensated for by allocating more descriptors using the TxDescriptors + module parameter. + + There are other conditions which may result in "TX Timeout", which will + not be resolved by the use of the TxDescriptorStep parameter. As the + issue addressed by this parameter has never been observed on Intel + Architecture platforms, it should not be used on Intel platforms. + +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 +------------- +(This parameter is supported only on 82540, 82545 and later adapters.) +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 +------ +(This parameter is NOT supported 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. + +Copybreak +--------- +Valid Range: 0-xxxxxxx (0=off) +Default Value: 256 +Usage: insmod e1000.ko copybreak=128 + +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/e1000/parameters/copybreak + +SmartPowerDownEnable +-------------------- +Valid Range: 0-1 +Default Value: 0 (disabled) + +Allows 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. + +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. It should be used when you wish to control which +speed and duplex combinations are advertised during the auto-negotiation +process. + +The parameter may be specified as either a decimal or hexadecimal value as +determined by the bitmap below. + +Bit position 7 6 5 4 3 2 1 0 +Decimal Value 128 64 32 16 8 4 2 1 +Hex value 80 40 20 10 8 4 2 1 +Speed (Mbps) N/A N/A 1000 N/A 100 100 10 10 +Duplex Full Full Half Full Half + +Some examples of using AutoNeg: + + modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half) + modprobe e1000 AutoNeg=1 (Same as above) + modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full) + modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full) + modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half) + modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100 + Half) + modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full) + modprobe e1000 AutoNeg=32 (Same as above) + +Note that when this parameter is used, Speed and Duplex must not be specified. + +If the link partner is forced to a specific speed and duplex, then this +parameter should not be used. Instead, use the Speed and Duplex parameters +previously mentioned to force the adapter to the same speed and duplex. + +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. It can be made permanent if + you add: + + MTU=9000 + + to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>. This example + applies to the Red Hat distributions; other distributions may store this + setting in a different location. + + Notes: + Degradation in throughput performance may be observed in some Jumbo frames + environments. If this is observed, increasing the application's socket buffer + size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help. + See the specific application manual and /usr/src/linux*/Documentation/ + networking/ip-sysctl.txt for more details. + + - The maximum MTU setting for Jumbo Frames is 16110. This value coincides + with the maximum Jumbo Frames size of 16128. + + - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in + poor performance or loss of link. + + - Adapters based on the Intel(R) 82542 and 82573V/E controller do not + support Jumbo Frames. These correspond to the following product names: + Intel(R) PRO/1000 Gigabit Server Adapter + Intel(R) PRO/1000 PM Network Connection + + ethtool + ------- + The driver utilizes the ethtool interface for driver configuration and + diagnostics, as well as displaying statistical information. The ethtool + version 1.6 or later is required for this functionality. + + The latest release of ethtool can be found from + http://ftp.kernel.org/pub/software/network/ethtool/ + + 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 e1000 driver must be + loaded when shutting down or rebooting the system. + +Support +======= + +For general information, go to the Intel support website at: + + http://support.intel.com + +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 |