path: root/Documentation/networking/s2io.txt
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authorAnton Arapov <>2012-04-16 10:05:28 +0200
committerAnton Arapov <>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /Documentation/networking/s2io.txt
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
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+Release notes for Neterion's (Formerly S2io) Xframe I/II PCI-X 10GbE driver.
+- 1. Introduction
+- 2. Identifying the adapter/interface
+- 3. Features supported
+- 4. Command line parameters
+- 5. Performance suggestions
+- 6. Available Downloads
+1. Introduction:
+This Linux driver supports Neterion's Xframe I PCI-X 1.0 and
+Xframe II PCI-X 2.0 adapters. It supports several features
+such as jumbo frames, MSI/MSI-X, checksum offloads, TSO, UFO and so on.
+See below for complete list of features.
+All features are supported for both IPv4 and IPv6.
+2. Identifying the adapter/interface:
+a. Insert the adapter(s) in your system.
+b. Build and load driver
+# insmod s2io.ko
+c. View log messages
+# dmesg | tail -40
+You will see messages similar to:
+eth3: Neterion Xframe I 10GbE adapter (rev 3), Version, Intr type INTA
+eth4: Neterion Xframe II 10GbE adapter (rev 2), Version, Intr type INTA
+eth4: Device is on 64 bit 133MHz PCIX(M1) bus
+The above messages identify the adapter type(Xframe I/II), adapter revision,
+driver version, interface name(eth3, eth4), Interrupt type(INTA, MSI, MSI-X).
+In case of Xframe II, the PCI/PCI-X bus width and frequency are displayed
+as well.
+To associate an interface with a physical adapter use "ethtool -p <ethX>".
+The corresponding adapter's LED will blink multiple times.
+3. Features supported:
+a. Jumbo frames. Xframe I/II supports MTU up to 9600 bytes,
+modifiable using ifconfig command.
+b. Offloads. Supports checksum offload(TCP/UDP/IP) on transmit
+and receive, TSO.
+c. Multi-buffer receive mode. Scattering of packet across multiple
+buffers. Currently driver supports 2-buffer mode which yields
+significant performance improvement on certain platforms(SGI Altix,
+IBM xSeries).
+d. MSI/MSI-X. Can be enabled on platforms which support this feature
+(IA64, Xeon) resulting in noticeable performance improvement(up to 7%
+on certain platforms).
+e. Statistics. Comprehensive MAC-level and software statistics displayed
+using "ethtool -S" option.
+f. Multi-FIFO/Ring. Supports up to 8 transmit queues and receive rings,
+with multiple steering options.
+4. Command line parameters
+a. tx_fifo_num
+Number of transmit queues
+Valid range: 1-8
+Default: 1
+b. rx_ring_num
+Number of receive rings
+Valid range: 1-8
+Default: 1
+c. tx_fifo_len
+Size of each transmit queue
+Valid range: Total length of all queues should not exceed 8192
+Default: 4096
+d. rx_ring_sz
+Size of each receive ring(in 4K blocks)
+Valid range: Limited by memory on system
+Default: 30
+e. intr_type
+Specifies interrupt type. Possible values 0(INTA), 2(MSI-X)
+Valid values: 0, 2
+Default: 2
+5. Performance suggestions
+a. Set MTU to maximum(9000 for switch setup, 9600 in back-to-back configuration)
+b. Set TCP windows size to optimal value.
+For instance, for MTU=1500 a value of 210K has been observed to result in
+good performance.
+# sysctl -w net.ipv4.tcp_rmem="210000 210000 210000"
+# sysctl -w net.ipv4.tcp_wmem="210000 210000 210000"
+For MTU=9000, TCP window size of 10 MB is recommended.
+# sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000"
+# sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000"
+Transmit performance:
+a. By default, the driver respects BIOS settings for PCI bus parameters.
+However, you may want to experiment with PCI bus parameters
+max-split-transactions(MOST) and MMRBC (use setpci command).
+A MOST value of 2 has been found optimal for Opterons and 3 for Itanium.
+It could be different for your hardware.
+Set MMRBC to 4K**.
+For example you can set
+For opteron
+#setpci -d 17d5:* 62=1d
+For Itanium
+#setpci -d 17d5:* 62=3d
+For detailed description of the PCI registers, please see Xframe User Guide.
+b. Ensure Transmit Checksum offload is enabled. Use ethtool to set/verify this
+c. Turn on TSO(using "ethtool -K")
+# ethtool -K <ethX> tso on
+Receive performance:
+a. By default, the driver respects BIOS settings for PCI bus parameters.
+However, you may want to set PCI latency timer to 248.
+#setpci -d 17d5:* LATENCY_TIMER=f8
+For detailed description of the PCI registers, please see Xframe User Guide.
+b. Use 2-buffer mode. This results in large performance boost on
+certain platforms(eg. SGI Altix, IBM xSeries).
+c. Ensure Receive Checksum offload is enabled. Use "ethtool -K ethX" command to
+set/verify this option.
+d. Enable NAPI feature(in kernel configuration Device Drivers ---> Network
+device support ---> Ethernet (10000 Mbit) ---> S2IO 10Gbe Xframe NIC) to
+bring down CPU utilization.
+** For AMD opteron platforms with 8131 chipset, MMRBC=1 and MOST=1 are
+recommended as safe parameters.
+For more information, please review the AMD8131 errata at
+6. Available Downloads
+Neterion "s2io" driver in Red Hat and Suse 2.6-based distributions is kept up
+to date, also the latest "s2io" code (including support for 2.4 kernels) is
+available via "Support" link on the Neterion site:
+For Xframe User Guide (Programming manual), visit ftp site,
+user: linuxdocs password: HALdocs
+7. Support
+For further support please contact either your 10GbE Xframe NIC vendor (IBM,
+HP, SGI etc.) or click on the "Support" link on the Neterion site: