freebsd-dev/sys/dev/ixl/README

	ixl FreeBSD* Base Driver and ixlv VF Driver for the
	     Intel XL710 Ethernet Controller Family

/*$FreeBSD$*/
================================================================

August 26, 2014


Contents
========

- Overview
- Supported Adapters
- The VF Driver
- Building and Installation
- Additional Configurations
- Known Limitations


Overview
========

This file describes the IXL FreeBSD* Base driver and the IXLV VF Driver
for the XL710 Ethernet Family of Adapters. The Driver has been developed
for use with FreeBSD 10.0 or later, but should be compatible with any
supported release.

For questions related to hardware requirements, refer to the documentation
supplied with your Intel XL710 adapter. All hardware requirements listed
apply for use with FreeBSD.


Supported Adapters
==================

The drivers in this release are compatible with XL710 and X710-based
Intel Ethernet Network Connections.


SFP+ Devices with Pluggable Optics
----------------------------------

SR Modules
----------
  Intel     DUAL RATE 1G/10G SFP+ SR (bailed)    FTLX8571D3BCV-IT
  Intel     DUAL RATE 1G/10G SFP+ SR (bailed)    AFBR-703SDZ-IN2

LR Modules
----------
  Intel     DUAL RATE 1G/10G SFP+ LR (bailed)    FTLX1471D3BCV-IT
  Intel     DUAL RATE 1G/10G SFP+ LR (bailed)    AFCT-701SDZ-IN2

QSFP+ Modules
-------------
  Intel     TRIPLE RATE 1G/10G/40G QSFP+ SR (bailed)    E40GQSFPSR
  Intel     TRIPLE RATE 1G/10G/40G QSFP+ LR (bailed)    E40GQSFPLR
    QSFP+ 1G speed is not supported on XL710 based devices.

X710/XL710 Based SFP+ adapters support all passive and active limiting direct
attach cables that comply with SFF-8431 v4.1 and SFF-8472 v10.4 specifications.
              
The VF Driver
==================
The VF driver is normally used in a virtualized environment where a host
driver manages SRIOV, and provides a VF device to the guest. With this
first release the only host environment tested was using Linux QEMU/KVM.
Support is planned for Xen and VMWare hosts at a later time.

In the FreeBSD guest the IXLV driver would be loaded and will function
using the VF device assigned to it.

The VF driver provides most of the same functionality as the CORE driver,
but is actually a slave to the Host, access to many controls are actually
accomplished by a request to the Host via what is called the "Admin queue".
These are startup and initialization events however, once in operation
the device is self-contained and should achieve near native performance.

Some notable limitations of the VF environment: for security reasons 
the driver is never permitted to be promiscuous, therefore a tcpdump
will not behave the same with the interface. Second, media info is not
available from the PF, so it will always appear as auto.

Tarball Building and Installation
=========================

NOTE: You must have kernel sources installed to compile the driver tarball.

These instructions assume a standalone driver tarball, building the driver
already in the kernel source is simply a matter of adding the device entry
to the kernel config file, or building in the ixl or ixlv module directory.

In the instructions below, x.x.x is the driver version
as indicated in the name of the driver tarball. The example is
for ixl, the same procedure applies for ixlv.

1. Move the base driver tar file to the directory of your choice.
   For example, use /home/username/ixl or /usr/local/src/ixl.

2. Untar/unzip the archive:
     tar xfz ixl-x.x.x.tar.gz

3. To install man page:
     cd ixl-x.x.x
     gzip -c ixl.4 > /usr/share/man/man4/ixl.4.gz

4. To load the driver onto a running system:
     cd ixl-x.x.x/src
     make load

5. To assign an IP address to the interface, enter the following:
     ifconfig ixl<interface_num> <IP_address>

6. Verify that the interface works. Enter the following, where <IP_address>
   is the IP address for another machine on the same subnet as the interface
   that is  being tested:

     ping <IP_address>

7. If you want the driver to load automatically when the system is booted:

     cd ixl-x.x.x/src
     make
     make install
        
    Edit /boot/loader.conf, and add the following line:
     if_ixl_load="YES"

    Edit /etc/rc.conf, and create the appropriate
    ifconfig_ixl<interface_num> entry:

     ifconfig_ixl<interface_num>="<ifconfig_settings>"

     Example usage:

     ifconfig_ixl0="inet 192.168.10.1 netmask 255.255.255.0"

     NOTE: For assistance, see the ifconfig man page.



Configuration and Tuning
=========================

Both drivers supports Transmit/Receive Checksum Offload for IPv4 and IPv6,
TSO forIPv4 and IPv6, LRO, and Jumbo Frames on all 40 Gigabit adapters. 

  Jumbo Frames
  ------------
  To enable Jumbo Frames, use the ifconfig utility to increase
  the MTU beyond 1500 bytes.

       - The Jumbo Frames setting on the switch must be set to at least
         22 byteslarger than that of the adapter.

       - The maximum MTU setting for Jumbo Frames is 9706. This value
         coincides with the maximum jumbo frames size of 9728.
         To modify the setting, enter the following:

        ifconfig ixl<interface_num> <hostname or IP address> mtu 9000

       - To confirm an interface's MTU value, use the ifconfig command.
         To confirm the MTU used between two specific devices, use:

        route get <destination_IP_address>

  VLANs
  -----
  To create a new VLAN pseudo-interface:

        ifconfig <vlan_name> create

  To associate the VLAN pseudo-interface with a physical interface
  and assign a VLAN ID, IP address, and netmask:

        ifconfig <vlan_name> <ip_address> netmask <subnet_mask> vlan
           <vlan_id> vlandev <physical_interface>

  Example:

        ifconfig vlan10 10.0.0.1 netmask 255.255.255.0 vlan 10 vlandev ixl0

  In this example, all packets will be marked on egress with
  802.1Q VLAN tags, specifying a VLAN ID of 10.

  To remove a VLAN pseudo-interface:

        ifconfig <vlan_name> destroy


  Checksum Offload
  ----------------
    
  Checksum offloading supports IPv4 and IPv6 with TCP and UDP packets
  and is supported for both transmit and receive. Checksum offloading
  for transmit and recieve is enabled by default for both IPv4 and IPv6.

  Checksum offloading can be enabled or disabled using ifconfig.
  Transmit and receive offloading for IPv4 and Ipv6 are enabled
  and disabled seperately.

  NOTE: TSO requires Tx checksum, so when Tx checksum
        is disabled, TSO will also  be disabled. 

  To enable Tx checksum offloading for ipv4:

         ifconfig ixl<interface_num> txcsum4 

  To disable Tx checksum offloading for ipv4:
         
         ifconfig ixl<interface_num> -txcsum4 
         (NOTE: This will disable TSO4)

  To enable Rx checksum offloading for ipv6:
 
         ifconfig ixl<interface_num> rxcsum6 
         
  To disable Rx checksum offloading for ipv6:

         ifconfig ixl<interface_num> -rxcsum6 
         (NOTE: This will disable TSO6)

  
  To confirm the current settings:

         ifconfig ixl<interface_num>

  
  TSO
  ---

  TSO supports both IPv4 and IPv6 and is enabled by default. TSO can
  be disabled and enabled using the ifconfig utility.

  NOTE: TSO requires Tx checksum, so when Tx checksum is
      disabled, TSO will also be disabled. 

  To disable TSO IPv4:

         ifconfig ixl<interface_num> -tso4
         
  To enable TSO IPv4:

         ifconfig ixl<interface_num> tso4 

  To disable TSO IPv6:

         ifconfig ixl<interface_num> -tso6

  To enable TSO IPv6:
        
         ifconfig ixl<interface_num> tso6

  To disable BOTH TSO IPv4 and IPv6:

         ifconfig ixl<interface_num> -tso

  To enable BOTH TSO IPv4 and IPv6:
  
         ifconfig ixl<interface_num> tso


  LRO
  ---

  Large Receive Offload is enabled by default. It can be enabled
  or disabled by using the ifconfig utility.

  NOTE: LRO should be disabled when forwarding packets.

  To disable LRO:	

         ifconfig ixl<interface_num> -lro 

  To enable LRO:

         ifconfig ixl<interface_num> lro 


Flow Control  (IXL only)
------------
Flow control is disabled by default. To change flow control settings use sysctl.

To enable flow control to Rx pause frames:     

         sysctl dev.ixl.<interface_num>.fc=1

To enable flow control to Tx pause frames: 

         sysctl dev.ixl.<interface_num>.fc=2

To enable flow control to Rx and Tx pause frames:

         sysctl dev.ixl.<interface_num>.fc=3

To disable flow control:

         sysctl dev.ixl.<interface_num>.fc=0
    

NOTE: You must have a flow control capable link partner.

NOTE: The VF driver does not have access to flow control, it must be
	managed from the host side.

   
  Important system configuration changes:
  =======================================
 
-Change the file /etc/sysctl.conf, and add the line:  
 
         hw.intr_storm_threshold: 0 (the default is 1000)

-Best throughput results are seen with a large MTU; use 9706 if possible. 

-The default number of descriptors per ring is 1024, increasing this may
improve performance depending on the use case.

-The VF driver uses a relatively large buf ring, this was found to eliminate
 UDP transmit errors, it is a tuneable, and if no UDP traffic is used it can
 be reduced. It is memory used per queue.


Known Limitations
=================

Network Memory Buffer allocation
--------------------------------
  FreeBSD may have a low number of network memory buffers (mbufs) by default.
If your mbuf value is too low, it may cause the driver to fail to initialize
and/or cause the system to become unresponsive. You can check to see if the
system is mbuf-starved by running 'netstat -m'. Increase the number of mbufs
by editing the lines below in /etc/sysctl.conf:

         kern.ipc.nmbclusters
         kern.ipc.nmbjumbop    
         kern.ipc.nmbjumbo9
         kern.ipc.nmbjumbo16
         kern.ipc.nmbufs

The amount of memory that you allocate is system specific, and may
require some trial and error.

Also, increasing the follwing in /etc/sysctl.conf could help increase
network performance:
         
         kern.ipc.maxsockbuf
         net.inet.tcp.sendspace
         net.inet.tcp.recvspace
         net.inet.udp.maxdgram
         net.inet.udp.recvspace
                  

UDP Stress Test Dropped Packet Issue
------------------------------------
Under small packet UDP stress test with the ixl driver, the FreeBSD system
may drop UDP packets due to the fullness of socket buffers. You may want to
change the driver's Flow Control variables to the minimum value for
controlling packet reception.


Disable LRO when routing/bridging
---------------------------------
LRO must be turned off when forwarding traffic.


Lower than expected performance
-------------------------------
Some PCIe x8 slots are actually configured as x4 slots. These slots have
insufficient bandwidth for full line rate with dual port and quad port
devices.

In addition, if you put a PCIe Generation 3-capable adapter into a PCIe
Generation 2 slot, you cannot get full bandwidth. The driver detects this
situation and writes the following message in the system log:

  "PCI-Express bandwidth available for this card is not sufficient for
   optimal  performance. For optimal performance a x8 PCI-Express slot
   is required."

If this error occurs, moving your adapter to a true PCIe Generation 3 x8
slot will resolve the issue.


Support
=======

For general information and support, go to the Intel support website at:

        http://support.intel.com

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 freebsdnic@mailbox.intel.com.


License
=======

This software program is released under the terms of a license agreement
between you ('Licensee') and Intel. Do not use or load this software or any
associated  materials (collectively, the 'Software') until you have carefully
read the full terms and conditions of the LICENSE located in this software
package. By loadingor using the Software, you agree to the terms of this
Agreement. If you do not agree with the terms of this Agreement, do not
install or use the Software.

* Other names and brands may be claimed as the property of others.