| 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: 48-256 for 82542 and 82543-based adapters |
| 48-4096 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: 48-256 for 82542 and 82543-based adapters |
| 48-4096 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: 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 |
| ------------- |
| (This parameter is supported only on 82540, 82545 and later adapters.) |
| 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. |
| |
| 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: modprobe 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. |
| |
| 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 |
| https://www.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 |
