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212 lines
8.5 KiB
Text
212 lines
8.5 KiB
Text
Linux* Base Driver for the Intel(R) PRO/10GbE Family of Adapters
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================================================================
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November 17, 2004
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Contents
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========
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- In This Release
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- Identifying Your Adapter
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- Command Line Parameters
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- Improving Performance
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- Support
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In This Release
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===============
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This file describes the Linux* Base Driver for the Intel(R) PRO/10GbE Family
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of Adapters, version 1.0.x.
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For questions related to hardware requirements, refer to the documentation
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supplied with your Intel PRO/10GbE adapter. All hardware requirements listed
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apply to use with Linux.
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Identifying Your Adapter
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========================
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To verify your Intel adapter is supported, find the board ID number on the
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adapter. Look for a label that has a barcode and a number in the format
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A12345-001.
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Use the above information and the Adapter & Driver ID Guide at:
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http://support.intel.com/support/network/adapter/pro100/21397.htm
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For the latest Intel network drivers for Linux, go to:
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http://downloadfinder.intel.com/scripts-df/support_intel.asp
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Command Line Parameters
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=======================
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If the driver is built as a module, the following optional parameters are
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used by entering them on the command line with the modprobe or insmod command
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using this syntax:
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modprobe ixgb [<option>=<VAL1>,<VAL2>,...]
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insmod ixgb [<option>=<VAL1>,<VAL2>,...]
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For example, with two PRO/10GbE PCI adapters, entering:
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insmod ixgb TxDescriptors=80,128
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loads the ixgb driver with 80 TX resources for the first adapter and 128 TX
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resources for the second adapter.
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The default value for each parameter is generally the recommended setting,
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unless otherwise noted. Also, if the driver is statically built into the
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kernel, the driver is loaded with the default values for all the parameters.
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Ethtool can be used to change some of the parameters at runtime.
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FlowControl
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Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)
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Default: Read from the EEPROM
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If EEPROM is not detected, default is 3
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This parameter controls the automatic generation(Tx) and response(Rx) to
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Ethernet PAUSE frames.
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RxDescriptors
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Valid Range: 64-512
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Default Value: 512
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This value is the number of receive descriptors allocated by the driver.
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Increasing this value allows the driver to buffer more incoming packets.
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Each descriptor is 16 bytes. A receive buffer is also allocated for
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each descriptor and can be either 2048, 4056, 8192, or 16384 bytes,
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depending on the MTU setting. When the MTU size is 1500 or less, the
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receive buffer size is 2048 bytes. When the MTU is greater than 1500 the
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receive buffer size will be either 4056, 8192, or 16384 bytes. The
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maximum MTU size is 16114.
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RxIntDelay
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Valid Range: 0-65535 (0=off)
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Default Value: 6
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This value delays the generation of receive interrupts in units of
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0.8192 microseconds. Receive interrupt reduction can improve CPU
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efficiency if properly tuned for specific network traffic. Increasing
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this value adds extra latency to frame reception and can end up
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decreasing the throughput of TCP traffic. If the system is reporting
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dropped receives, this value may be set too high, causing the driver to
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run out of available receive descriptors.
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TxDescriptors
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Valid Range: 64-4096
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Default Value: 256
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This value is the number of transmit descriptors allocated by the driver.
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Increasing this value allows the driver to queue more transmits. Each
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descriptor is 16 bytes.
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XsumRX
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Valid Range: 0-1
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Default Value: 1
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A value of '1' indicates that the driver should enable IP checksum
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offload for received packets (both UDP and TCP) to the adapter hardware.
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XsumTX
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Valid Range: 0-1
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Default Value: 1
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A value of '1' indicates that the driver should enable IP checksum
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offload for transmitted packets (both UDP and TCP) to the adapter
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hardware.
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Improving Performance
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=====================
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With the Intel PRO/10 GbE adapter, the default Linux configuration will very
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likely limit the total available throughput artificially. There is a set of
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things that when applied together increase the ability of Linux to transmit
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and receive data. The following enhancements were originally acquired from
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settings published at http://www.spec.org/web99 for various submitted results
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using Linux.
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NOTE: These changes are only suggestions, and serve as a starting point for
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tuning your network performance.
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The changes are made in three major ways, listed in order of greatest effect:
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- Use ifconfig to modify the mtu (maximum transmission unit) and the txqueuelen
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parameter.
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- Use sysctl to modify /proc parameters (essentially kernel tuning)
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- Use setpci to modify the MMRBC field in PCI-X configuration space to increase
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transmit burst lengths on the bus.
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NOTE: setpci modifies the adapter's configuration registers to allow it to read
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up to 4k bytes at a time (for transmits). However, for some systems the
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behavior after modifying this register may be undefined (possibly errors of some
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kind). A power-cycle, hard reset or explicitly setting the e6 register back to
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22 (setpci -d 8086:1048 e6.b=22) may be required to get back to a stable
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configuration.
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- COPY these lines and paste them into ixgb_perf.sh:
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#!/bin/bash
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echo "configuring network performance , edit this file to change the interface"
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# set mmrbc to 4k reads, modify only Intel 10GbE device IDs
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setpci -d 8086:1048 e6.b=2e
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# set the MTU (max transmission unit) - it requires your switch and clients to change too!
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# set the txqueuelen
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# your ixgb adapter should be loaded as eth1 for this to work, change if needed
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ifconfig eth1 mtu 9000 txqueuelen 1000 up
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# call the sysctl utility to modify /proc/sys entries
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sysctl -p ./sysctl_ixgb.conf
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- END ixgb_perf.sh
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- COPY these lines and paste them into sysctl_ixgb.conf:
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# some of the defaults may be different for your kernel
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# call this file with sysctl -p <this file>
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# these are just suggested values that worked well to increase throughput in
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# several network benchmark tests, your mileage may vary
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### IPV4 specific settings
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net.ipv4.tcp_timestamps = 0 # turns TCP timestamp support off, default 1, reduces CPU use
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net.ipv4.tcp_sack = 0 # turn SACK support off, default on
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# on systems with a VERY fast bus -> memory interface this is the big gainer
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net.ipv4.tcp_rmem = 10000000 10000000 10000000 # sets min/default/max TCP read buffer, default 4096 87380 174760
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net.ipv4.tcp_wmem = 10000000 10000000 10000000 # sets min/pressure/max TCP write buffer, default 4096 16384 131072
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net.ipv4.tcp_mem = 10000000 10000000 10000000 # sets min/pressure/max TCP buffer space, default 31744 32256 32768
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### CORE settings (mostly for socket and UDP effect)
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net.core.rmem_max = 524287 # maximum receive socket buffer size, default 131071
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net.core.wmem_max = 524287 # maximum send socket buffer size, default 131071
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net.core.rmem_default = 524287 # default receive socket buffer size, default 65535
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net.core.wmem_default = 524287 # default send socket buffer size, default 65535
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net.core.optmem_max = 524287 # maximum amount of option memory buffers, default 10240
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net.core.netdev_max_backlog = 300000 # number of unprocessed input packets before kernel starts dropping them, default 300
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- END sysctl_ixgb.conf
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Edit the ixgb_perf.sh script if necessary to change eth1 to whatever interface
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your ixgb driver is using.
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NOTE: Unless these scripts are added to the boot process, these changes will
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only last only until the next system reboot.
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Resolving Slow UDP Traffic
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--------------------------
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If your server does not seem to be able to receive UDP traffic as fast as it
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can receive TCP traffic, it could be because Linux, by default, does not set
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the network stack buffers as large as they need to be to support high UDP
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transfer rates. One way to alleviate this problem is to allow more memory to
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be used by the IP stack to store incoming data.
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For instance, use the commands:
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sysctl -w net.core.rmem_max=262143
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and
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sysctl -w net.core.rmem_default=262143
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to increase the read buffer memory max and default to 262143 (256k - 1) from
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defaults of max=131071 (128k - 1) and default=65535 (64k - 1). These variables
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will increase the amount of memory used by the network stack for receives, and
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can be increased significantly more if necessary for your application.
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Support
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=======
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For general information and support, go to the Intel support website at:
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http://support.intel.com
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If an issue is identified with the released source code on the supported
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kernel with a supported adapter, email the specific information related to
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the issue to linux.nics@intel.com.
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