linux/Documentation/networking/s2io.txt
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   1Release notes for Neterion's (Formerly S2io) Xframe I/II PCI-X 10GbE driver.
   2
   3Contents
   4=======
   5- 1.  Introduction
   6- 2.  Identifying the adapter/interface
   7- 3.  Features supported
   8- 4.  Command line parameters
   9- 5.  Performance suggestions
  10- 6.  Available Downloads 
  11
  12
  131.      Introduction:
  14This Linux driver supports Neterion's Xframe I PCI-X 1.0 and
  15Xframe II PCI-X 2.0 adapters. It supports several features 
  16such as jumbo frames, MSI/MSI-X, checksum offloads, TSO, UFO and so on.
  17See below for complete list of features.
  18All features are supported for both IPv4 and IPv6.
  19
  202.      Identifying the adapter/interface:
  21a. Insert the adapter(s) in your system.
  22b. Build and load driver 
  23# insmod s2io.ko
  24c. View log messages
  25# dmesg | tail -40
  26You will see messages similar to:
  27eth3: Neterion Xframe I 10GbE adapter (rev 3), Version 2.0.9.1, Intr type INTA
  28eth4: Neterion Xframe II 10GbE adapter (rev 2), Version 2.0.9.1, Intr type INTA
  29eth4: Device is on 64 bit 133MHz PCIX(M1) bus
  30
  31The above messages identify the adapter type(Xframe I/II), adapter revision,
  32driver version, interface name(eth3, eth4), Interrupt type(INTA, MSI, MSI-X).
  33In case of Xframe II, the PCI/PCI-X bus width and frequency are displayed
  34as well.
  35
  36To associate an interface with a physical adapter use "ethtool -p <ethX>".
  37The corresponding adapter's LED will blink multiple times.
  38
  393.      Features supported:
  40a. Jumbo frames. Xframe I/II supports MTU up to 9600 bytes,
  41modifiable using ifconfig command.
  42
  43b. Offloads. Supports checksum offload(TCP/UDP/IP) on transmit
  44and receive, TSO.
  45
  46c. Multi-buffer receive mode. Scattering of packet across multiple
  47buffers. Currently driver supports 2-buffer mode which yields
  48significant performance improvement on certain platforms(SGI Altix,
  49IBM xSeries).
  50
  51d. MSI/MSI-X. Can be enabled on platforms which support this feature
  52(IA64, Xeon) resulting in noticeable performance improvement(up to 7%
  53on certain platforms).
  54
  55e. Statistics. Comprehensive MAC-level and software statistics displayed
  56using "ethtool -S" option.
  57
  58f. Multi-FIFO/Ring. Supports up to 8 transmit queues and receive rings,
  59with multiple steering options.
  60
  614.  Command line parameters
  62a. tx_fifo_num
  63Number of transmit queues
  64Valid range: 1-8
  65Default: 1
  66
  67b. rx_ring_num
  68Number of receive rings
  69Valid range: 1-8
  70Default: 1
  71
  72c. tx_fifo_len
  73Size of each transmit queue
  74Valid range: Total length of all queues should not exceed 8192
  75Default: 4096
  76
  77d. rx_ring_sz 
  78Size of each receive ring(in 4K blocks)
  79Valid range: Limited by memory on system
  80Default: 30 
  81
  82e. intr_type
  83Specifies interrupt type. Possible values 0(INTA), 2(MSI-X)
  84Valid values: 0, 2
  85Default: 2
  86
  875.  Performance suggestions
  88General:
  89a. Set MTU to maximum(9000 for switch setup, 9600 in back-to-back configuration)
  90b. Set TCP windows size to optimal value. 
  91For instance, for MTU=1500 a value of 210K has been observed to result in 
  92good performance.
  93# sysctl -w net.ipv4.tcp_rmem="210000 210000 210000"
  94# sysctl -w net.ipv4.tcp_wmem="210000 210000 210000"
  95For MTU=9000, TCP window size of 10 MB is recommended.
  96# sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000"
  97# sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000"
  98
  99Transmit performance:
 100a. By default, the driver respects BIOS settings for PCI bus parameters. 
 101However, you may want to experiment with PCI bus parameters 
 102max-split-transactions(MOST) and MMRBC (use setpci command). 
 103A MOST value of 2 has been found optimal for Opterons and 3 for Itanium.  
 104It could be different for your hardware.  
 105Set MMRBC to 4K**.
 106
 107For example you can set 
 108For opteron
 109#setpci -d 17d5:* 62=1d 
 110For Itanium
 111#setpci -d 17d5:* 62=3d 
 112
 113For detailed description of the PCI registers, please see Xframe User Guide.
 114
 115b. Ensure Transmit Checksum offload is enabled. Use ethtool to set/verify this 
 116parameter.
 117c. Turn on TSO(using "ethtool -K")
 118# ethtool -K <ethX> tso on
 119
 120Receive performance:
 121a. By default, the driver respects BIOS settings for PCI bus parameters. 
 122However, you may want to set PCI latency timer to 248.
 123#setpci -d 17d5:* LATENCY_TIMER=f8
 124For detailed description of the PCI registers, please see Xframe User Guide.
 125b. Use 2-buffer mode. This results in large performance boost on
 126certain platforms(eg. SGI Altix, IBM xSeries).
 127c. Ensure Receive Checksum offload is enabled. Use "ethtool -K ethX" command to 
 128set/verify this option.
 129d. Enable NAPI feature(in kernel configuration Device Drivers ---> Network 
 130device support --->  Ethernet (10000 Mbit) ---> S2IO 10Gbe Xframe NIC) to 
 131bring down CPU utilization.
 132
 133** For AMD opteron platforms with 8131 chipset, MMRBC=1 and MOST=1 are 
 134recommended as safe parameters.
 135For more information, please review the AMD8131 errata at
 136http://vip.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/
 13726310_AMD-8131_HyperTransport_PCI-X_Tunnel_Revision_Guide_rev_3_18.pdf
 138
 1396. Support
 140For further support please contact either your 10GbE Xframe NIC vendor (IBM, 
 141HP, SGI etc.)
 142
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