/spare/repo/netdev-2.6 branch 'chelsio'

                 Chelsio N210 10Gb Ethernet Network Controller

                         Driver Release Notes for Linux

                                 Version 2.1.1

                                 June 20, 2005

CONTENTS

========

 INTRODUCTION

 FEATURES

 PERFORMANCE

 DRIVER MESSAGES

 KNOWN ISSUES

 SUPPORT

INTRODUCTION

============

 This document describes the Linux driver for Chelsio 10Gb Ethernet Network

 Controller. This driver supports the Chelsio N210 NIC and is backward

 compatible with the Chelsio N110 model 10Gb NICs.

FEATURES

========

 Adaptive Interrupts (adaptive-rx)

 ---------------------------------

  This feature provides an adaptive algorithm that adjusts the interrupt

  coalescing parameters, allowing the driver to dynamically adapt the latency

  settings to achieve the highest performance during various types of network

  load.

  The interface used to control this feature is ethtool. Please see the

  ethtool manpage for additional usage information.

  By default, adaptive-rx is disabled.

  To enable adaptive-rx:

      ethtool -C <interface> adaptive-rx on

  To disable adaptive-rx, use ethtool:

      ethtool -C <interface> adaptive-rx off

  After disabling adaptive-rx, the timer latency value will be set to 50us.

  You may set the timer latency after disabling adaptive-rx:

      ethtool -C <interface> rx-usecs <microseconds>

  An example to set the timer latency value to 100us on eth0:

      ethtool -C eth0 rx-usecs 100

  You may also provide a timer latency value while disabling adpative-rx:

      ethtool -C <interface> adaptive-rx off rx-usecs <microseconds>

  If adaptive-rx is disabled and a timer latency value is specified, the timer

  will be set to the specified value until changed by the user or until

  adaptive-rx is enabled.

  To view the status of the adaptive-rx and timer latency values:

      ethtool -c <interface>

 TCP Segmentation Offloading (TSO) Support

 -----------------------------------------

  This feature, also known as "large send", enables a system's protocol stack

  to offload portions of outbound TCP processing to a network interface card

  thereby reducing system CPU utilization and enhancing performance.

  The interface used to control this feature is ethtool version 1.8 or higher.

  Please see the ethtool manpage for additional usage information.

  By default, TSO is enabled.

  To disable TSO:

      ethtool -K <interface> tso off

  To enable TSO:

      ethtool -K <interface> tso on

  To view the status of TSO:

      ethtool -k <interface>

PERFORMANCE

===========

 The following information is provided as an example of how to change system

 parameters for "performance tuning" an what value to use. You may or may not

 want to change these system parameters, depending on your server/workstation

 application. Doing so is not warranted in any way by Chelsio Communications,

 and is done at "YOUR OWN RISK". Chelsio will not be held responsible for loss

 of data or damage to equipment.

 Your distribution may have a different way of doing things, or you may prefer

 a different method. These commands are shown only to provide an example of

 what to do and are by no means definitive.

 Making any of the following system changes will only last until you reboot

 your system. You may want to write a script that runs at boot-up which

 includes the optimal settings for your system.

  Setting PCI Latency Timer:

      setpci -d 1425:* 0x0c.l=0x0000F800

  Disabling TCP timestamp:

      sysctl -w net.ipv4.tcp_timestamps=0

  Disabling SACK:

      sysctl -w net.ipv4.tcp_sack=0

  Setting large number of incoming connection requests:

      sysctl -w net.ipv4.tcp_max_syn_backlog=3000

  Setting maximum receive socket buffer size:

      sysctl -w net.core.rmem_max=1024000

  Setting maximum send socket buffer size:

      sysctl -w net.core.wmem_max=1024000

  Set smp_affinity (on a multiprocessor system) to a single CPU:

      echo 1 > /proc/irq/<interrupt_number>/smp_affinity

  Setting default receive socket buffer size:

      sysctl -w net.core.rmem_default=524287

  Setting default send socket buffer size:

      sysctl -w net.core.wmem_default=524287

  Setting maximum option memory buffers:

      sysctl -w net.core.optmem_max=524287

  Setting maximum backlog (# of unprocessed packets before kernel drops):

      sysctl -w net.core.netdev_max_backlog=300000

  Setting TCP read buffers (min/default/max):

      sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000"

  Setting TCP write buffers (min/pressure/max):

      sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000"

  Setting TCP buffer space (min/pressure/max):

      sysctl -w net.ipv4.tcp_mem="10000000 10000000 10000000"

  TCP window size for single connections:

   The receive buffer (RX_WINDOW) size must be at least as large as the

   Bandwidth-Delay Product of the communication link between the sender and

   receiver. Due to the variations of RTT, you may want to increase the buffer

   size up to 2 times the Bandwidth-Delay Product. Reference page 289 of

   "TCP/IP Illustrated, Volume 1, The Protocols" by W. Richard Stevens.

   At 10Gb speeds, use the following formula:

       RX_WINDOW >= 1.25MBytes * RTT(in milliseconds)

       Example for RTT with 100us: RX_WINDOW = (1,250,000 * 0.1) = 125,000

   RX_WINDOW sizes of 256KB - 512KB should be sufficient.

   Setting the min, max, and default receive buffer (RX_WINDOW) size:

       sysctl -w net.ipv4.tcp_rmem="<min> <default> <max>"

  TCP window size for multiple connections:

   The receive buffer (RX_WINDOW) size may be calculated the same as single

   connections, but should be divided by the number of connections. The

   smaller window prevents congestion and facilitates better pacing,

   especially if/when MAC level flow control does not work well or when it is

   not supported on the machine. Experimentation may be necessary to attain

   the correct value. This method is provided as a starting point fot the

   correct receive buffer size.

   Setting the min, max, and default receive buffer (RX_WINDOW) size is

   performed in the same manner as single connection.

DRIVER MESSAGES

===============

 The following messages are the most common messages logged by syslog. These

 may be found in /var/log/messages.

  Driver up:

     Chelsio Network Driver - version 2.1.1

  NIC detected:

     eth#: Chelsio N210 1x10GBaseX NIC (rev #), PCIX 133MHz/64-bit

  Link up:

     eth#: link is up at 10 Gbps, full duplex

  Link down:

     eth#: link is down

KNOWN ISSUES

============

 These issues have been identified during testing. The following information

 is provided as a workaround to the problem. In some cases, this problem is

 inherent to Linux or to a particular Linux Distribution and/or hardware

 platform.

  1. Large number of TCP retransmits on a multiprocessor (SMP) system.

      On a system with multiple CPUs, the interrupt (IRQ) for the network

      controller may be bound to more than one CPU. This will cause TCP

      retransmits if the packet data were to be split across different CPUs

      and re-assembled in a different order than expected.

      To eliminate the TCP retransmits, set smp_affinity on the particular

      interrupt to a single CPU. You can locate the interrupt (IRQ) used on

      the N110/N210 by using ifconfig:

          ifconfig <dev_name> | grep Interrupt

      Set the smp_affinity to a single CPU:

          echo 1 > /proc/irq/<interrupt_number>/smp_affinity

      It is highly suggested that you do not run the irqbalance daemon on your

      system, as this will change any smp_affinity setting you have applied.

      The irqbalance daemon runs on a 10 second interval and binds interrupts

      to the least loaded CPU determined by the daemon. To disable this daemon:

          chkconfig --level 2345 irqbalance off

      By default, some Linux distributions enable the kernel feature,

      irqbalance, which performs the same function as the daemon. To disable

      this feature, add the following line to your bootloader:

          noirqbalance

          Example using the Grub bootloader:

              title Red Hat Enterprise Linux AS (2.4.21-27.ELsmp)

              root (hd0,0)

              kernel /vmlinuz-2.4.21-27.ELsmp ro root=/dev/hda3 noirqbalance

              initrd /initrd-2.4.21-27.ELsmp.img

  2. After running insmod, the driver is loaded and the incorrect network

     interface is brought up without running ifup.

      When using 2.4.x kernels, including RHEL kernels, the Linux kernel

      invokes a script named "hotplug". This script is primarily used to

      automatically bring up USB devices when they are plugged in, however,

      the script also attempts to automatically bring up a network interface

      after loading the kernel module. The hotplug script does this by scanning

      the ifcfg-eth# config files in /etc/sysconfig/network-scripts, looking

      for HWADDR=<mac_address>.

      If the hotplug script does not find the HWADDRR within any of the

      ifcfg-eth# files, it will bring up the device with the next available

      interface name. If this interface is already configured for a different

      network card, your new interface will have incorrect IP address and

      network settings.

      To solve this issue, you can add the HWADDR=<mac_address> key to the

      interface config file of your network controller.

      To disable this "hotplug" feature, you may add the driver (module name)

      to the "blacklist" file located in /etc/hotplug. It has been noted that

      this does not work for network devices because the net.agent script

      does not use the blacklist file. Simply remove, or rename, the net.agent

      script located in /etc/hotplug to disable this feature.

  3. Transport Protocol (TP) hangs when running heavy multi-connection traffic

     on an AMD Opteron system with HyperTransport PCI-X Tunnel chipset.

      If your AMD Opteron system uses the AMD-8131 HyperTransport PCI-X Tunnel

      chipset, you may experience the "133-Mhz Mode Split Completion Data

      Corruption" bug identified by AMD while using a 133Mhz PCI-X card on the

      bus PCI-X bus.

      AMD states, "Under highly specific conditions, the AMD-8131 PCI-X Tunnel

      can provide stale data via split completion cycles to a PCI-X card that

      is operating at 133 Mhz", causing data corruption.

      AMD's provides three workarounds for this problem, however, Chelsio

      recommends the first option for best performance with this bug:

        For 133Mhz secondary bus operation, limit the transaction length and

        the number of outstanding transactions, via BIOS configuration

        programming of the PCI-X card, to the following:

           Data Length (bytes): 1k

           Total allowed outstanding transactions: 2

      Please refer to AMD 8131-HT/PCI-X Errata 26310 Rev 3.08 August 2004,

      section 56, "133-MHz Mode Split Completion Data Corruption" for more

      details with this bug and workarounds suggested by AMD.

      It may be possible to work outside AMD's recommended PCI-X settings, try

      increasing the Data Length to 2k bytes for increased performance. If you

      have issues with these settings, please revert to the "safe" settings

      and duplicate the problem before submitting a bug or asking for support.

      NOTE: The default setting on most systems is 8 outstanding transactions

            and 2k bytes data length.

  4. On multiprocessor systems, it has been noted that an application which

     is handling 10Gb networking can switch between CPUs causing degraded

     and/or unstable performance.

      If running on an SMP system and taking performance measurements, it

      is suggested you either run the latest netperf-2.4.0+ or use a binding

      tool such as Tim Hockin's procstate utilities (runon)

      <http://www.hockin.org/~thockin/procstate/>.

      Binding netserver and netperf (or other applications) to particular

      CPUs will have a significant difference in performance measurements.

      You may need to experiment which CPU to bind the application to in

      order to achieve the best performance for your system.

      If you are developing an application designed for 10Gb networking,

      please keep in mind you may want to look at kernel functions

      sched_setaffinity & sched_getaffinity to bind your application.

      If you are just running user-space applications such as ftp, telnet,

      etc., you may want to try the runon tool provided by Tim Hockin's

      procstate utility. You could also try binding the interface to a

      particular CPU: runon 0 ifup eth0

SUPPORT

=======

 If you have problems with the software or hardware, please contact our

 customer support team via email at support@chelsio.com or check our website

 at http://www.chelsio.com

===============================================================================

 Chelsio Communications

 370 San Aleso Ave.

 Suite 100

 Sunnyvale, CA 94085

 http://www.chelsio.com

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License, version 2, as

published by the Free Software Foundation.

You should have received a copy of the GNU General Public License along

with this program; if not, write to the Free Software Foundation, Inc.,

59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED

WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 Copyright (c) 2003-2005 Chelsio Communications. All rights reserved.

===============================================================================

menu "Ethernet (10000 Mbit)"

	depends on !UML

config CHELSIO_T1

        tristate "Chelsio 10Gb Ethernet support"

        depends on PCI

        help

          This driver supports Chelsio N110 and N210 models 10Gb Ethernet

          cards. More information about adapter features and performance

          tuning is in <file:Documentation/networking/cxgb.txt>.

          For general information about Chelsio and our products, visit

          our website at <http://www.chelsio.com>.

          For customer support, please visit our customer support page at

          <http://www.chelsio.com/support.htm>.

          Please send feedback to <linux-bugs@chelsio.com>.

          To compile this driver as a module, choose M here: the module

          will be called cxgb.

config IXGB

	tristate "Intel(R) PRO/10GbE support"

	depends on PCI

obj-$(CONFIG_E1000) += e1000/

obj-$(CONFIG_IBM_EMAC) += ibm_emac/

obj-$(CONFIG_IXGB) += ixgb/

obj-$(CONFIG_CHELSIO_T1) += chelsio/

obj-$(CONFIG_BONDING) += bonding/

obj-$(CONFIG_GIANFAR) += gianfar_driver.o

#

# Chelsio 10Gb NIC driver for Linux.

#

obj-$(CONFIG_CHELSIO_T1) += cxgb.o

EXTRA_CFLAGS += -I$(TOPDIR)/drivers/net/chelsio $(DEBUG_FLAGS)

cxgb-objs := cxgb2.o espi.o pm3393.o sge.o subr.o mv88x201x.o