[v2] Documentation: e1000e: Update kernel documentation

Message ID 20180412203600.18829-1-jeffrey.t.kirsher@intel.com
State Under Review
Delegated to: Jeff Kirsher
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  • [v2] Documentation: e1000e: Update kernel documentation
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Commit Message

Jeff Kirsher April 12, 2018, 8:36 p.m.
Updated the e1000e.txt kernel documentation with the latest information.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
v2: fixed up documentation based on community feedback and internal
    review

---
 Documentation/networking/e1000e.txt | 460 ++++++++++++++++++------------------
 1 file changed, 233 insertions(+), 227 deletions(-)

Patch

diff --git a/Documentation/networking/e1000e.txt b/Documentation/networking/e1000e.txt
index 12089547baed..e9dd18e1d2c6 100644
--- a/Documentation/networking/e1000e.txt
+++ b/Documentation/networking/e1000e.txt
@@ -2,7 +2,7 @@  Linux* Driver for Intel(R) Ethernet Network Connection
 ======================================================
 
 Intel Gigabit Linux driver.
-Copyright(c) 1999 - 2013 Intel Corporation.
+Copyright(c) 1999-2018 Intel Corporation.
 
 Contents
 ========
@@ -13,300 +13,306 @@  Contents
 - 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:
+http://www.intel.com/support
 
-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
-=======================
-
+-----------------------
+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.
 
-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
+NOTE: For more information about the command line parameters, see the
+application note at: http://www.intel.com/design/network/applnots/ap450.htm.
+
+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 (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.
+Valid Range:
+0=off
+1=dynamic
+4=simplified balancing
+<min_ITR>-<max_ITR>
+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.
+0 = Setting InterruptThrottleRate to 0 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.
+  NOTES:
+  - On 82599, and X540, and X550-based adapters, disabling InterruptThrottleRate
+    will also result in the driver disabling HW RSC.
+  - On 82598-based adapters, disabling InterruptThrottleRate will also
+    result in disabling LRO (Large Receive Offloads).
+1 = Setting InterruptThrottleRate to Dynamic 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.
+<min_ITR>-<max_ITR> =
+  Setting InterruptThrottleRate to a value greater or equal to <min_ITR>
+  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
-
+Valid Range: 0-65535 (0=off)
 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.
+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
-
+Valid Range: 0-65535 (0=off)
 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.
+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
+Valid Range: 0-65535 (0=off)
+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.
 
-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
-
+Valid Range: 0-65535 (0=off)
 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.
+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
 
-Driver copies all packets below or equaling this size to a fresh RX
+copybreak
+---------
+Valid Range: 0-xxxxxxx (0=off)
+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
 
-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 turn off this
+parameter in supported chipsets.
 
-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.
 
-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
+Valid Range: 0-2 (0 = Legacy Int, 1 = MSI and 2 = MSI-X)
+IntMode controls allow 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.
+'cat /proc/interrupts' will show different values for each type of interrupt.
 
-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
+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/
+Additional Features and Configurations
+-------------------------------------------
 
-  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.
+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:
+/etc/sysconfig/network-scripts/ifcfg-eth<x> for RHEL or to the file
+/etc/sysconfig/network/<config_file> for SLES.
+
+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
+- 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:
+http://ftp.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. ethtool is included with all versions of Red Hat after Red
+Hat 7.2. For the latest version, download and install ethtool from the
+following website:
+
+   http://ftp.kernel.org/pub/software/network/ethtool/
+
+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. ethtool is included with all
+versions of Red Hat after Red Hat 7.2. For other Linux distributions, download
+and install ethtool from the following website:
+http://ftp.kernel.org/pub/software/network/ethtool/.
+
+For instructions on enabling WoL with ethtool, refer to the website listed
+above.
+
+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
 
-  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/
+http://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
+http://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.