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diff --git a/Documentation/networking/ixgb.txt b/Documentation/networking/ixgb.txt new file mode 100644 index 000000000000..7c98277777eb --- /dev/null +++ b/Documentation/networking/ixgb.txt @@ -0,0 +1,212 @@ +Linux* Base Driver for the Intel(R) PRO/10GbE Family of Adapters +================================================================ + +November 17, 2004 + + +Contents +======== + +- In This Release +- Identifying Your Adapter +- Command Line Parameters +- Improving Performance +- Support + + +In This Release +=============== + +This file describes the Linux* Base Driver for the Intel(R) PRO/10GbE Family +of Adapters, version 1.0.x. + +For questions related to hardware requirements, refer to the documentation +supplied with your Intel PRO/10GbE adapter. All hardware requirements listed +apply to use with Linux. + +Identifying Your Adapter +======================== + +To verify your Intel adapter is supported, find the board ID number on the +adapter. Look for a label that has a barcode and a number in the format +A12345-001. + +Use the above information and the Adapter & Driver ID Guide at: + + http://support.intel.com/support/network/adapter/pro100/21397.htm + +For the latest Intel network drivers for Linux, go to: + + http://downloadfinder.intel.com/scripts-df/support_intel.asp + +Command Line Parameters +======================= + +If the driver is built as a module, the following optional parameters are +used by entering them on the command line with the modprobe or insmod command +using this syntax: + + modprobe ixgb [<option>=<VAL1>,<VAL2>,...] + + insmod ixgb [<option>=<VAL1>,<VAL2>,...] + +For example, with two PRO/10GbE PCI adapters, entering: + + insmod ixgb TxDescriptors=80,128 + +loads the ixgb driver with 80 TX resources for the first adapter and 128 TX +resources for the second adapter. + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. Also, if the driver is statically built into the +kernel, the driver is loaded with the default values for all the parameters. +Ethtool can be used to change some of the parameters at runtime. + +FlowControl +Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) +Default: Read from the EEPROM + If EEPROM is not detected, default is 3 + This parameter controls the automatic generation(Tx) and response(Rx) to + Ethernet PAUSE frames. + +RxDescriptors +Valid Range: 64-512 +Default Value: 512 + This value is the number of receive descriptors allocated by the driver. + Increasing this value allows the driver to buffer more incoming packets. + Each descriptor is 16 bytes. A receive buffer is also allocated for + each descriptor and can be either 2048, 4056, 8192, or 16384 bytes, + depending on the MTU setting. When the MTU size is 1500 or less, the + receive buffer size is 2048 bytes. When the MTU is greater than 1500 the + receive buffer size will be either 4056, 8192, or 16384 bytes. The + maximum MTU size is 16114. + +RxIntDelay +Valid Range: 0-65535 (0=off) +Default Value: 6 + This value delays the generation of receive interrupts in units of + 0.8192 microseconds. Receive interrupt reduction can improve CPU + efficiency if properly tuned for specific network traffic. Increasing + this value adds extra latency to frame reception and can end up + decreasing the throughput of TCP traffic. If the system is reporting + dropped receives, this value may be set too high, causing the driver to + run out of available receive descriptors. + +TxDescriptors +Valid Range: 64-4096 +Default Value: 256 + This value is the number of transmit descriptors allocated by the driver. + Increasing this value allows the driver to queue more transmits. Each + descriptor is 16 bytes. + +XsumRX +Valid Range: 0-1 +Default Value: 1 + A value of '1' indicates that the driver should enable IP checksum + offload for received packets (both UDP and TCP) to the adapter hardware. + +XsumTX +Valid Range: 0-1 +Default Value: 1 + A value of '1' indicates that the driver should enable IP checksum + offload for transmitted packets (both UDP and TCP) to the adapter + hardware. + +Improving Performance +===================== + +With the Intel PRO/10 GbE adapter, the default Linux configuration will very +likely limit the total available throughput artificially. There is a set of +things that when applied together increase the ability of Linux to transmit +and receive data. The following enhancements were originally acquired from +settings published at http://www.spec.org/web99 for various submitted results +using Linux. + +NOTE: These changes are only suggestions, and serve as a starting point for +tuning your network performance. + +The changes are made in three major ways, listed in order of greatest effect: +- Use ifconfig to modify the mtu (maximum transmission unit) and the txqueuelen + parameter. +- Use sysctl to modify /proc parameters (essentially kernel tuning) +- Use setpci to modify the MMRBC field in PCI-X configuration space to increase + transmit burst lengths on the bus. + +NOTE: setpci modifies the adapter's configuration registers to allow it to read +up to 4k bytes at a time (for transmits). However, for some systems the +behavior after modifying this register may be undefined (possibly errors of some +kind). A power-cycle, hard reset or explicitly setting the e6 register back to +22 (setpci -d 8086:1048 e6.b=22) may be required to get back to a stable +configuration. + +- COPY these lines and paste them into ixgb_perf.sh: +#!/bin/bash +echo "configuring network performance , edit this file to change the interface" +# set mmrbc to 4k reads, modify only Intel 10GbE device IDs +setpci -d 8086:1048 e6.b=2e +# set the MTU (max transmission unit) - it requires your switch and clients to change too! +# set the txqueuelen +# your ixgb adapter should be loaded as eth1 for this to work, change if needed +ifconfig eth1 mtu 9000 txqueuelen 1000 up +# call the sysctl utility to modify /proc/sys entries +sysctl -p ./sysctl_ixgb.conf +- END ixgb_perf.sh + +- COPY these lines and paste them into sysctl_ixgb.conf: +# some of the defaults may be different for your kernel +# call this file with sysctl -p <this file> +# these are just suggested values that worked well to increase throughput in +# several network benchmark tests, your mileage may vary + +### IPV4 specific settings +net.ipv4.tcp_timestamps = 0 # turns TCP timestamp support off, default 1, reduces CPU use +net.ipv4.tcp_sack = 0 # turn SACK support off, default on +# on systems with a VERY fast bus -> memory interface this is the big gainer +net.ipv4.tcp_rmem = 10000000 10000000 10000000 # sets min/default/max TCP read buffer, default 4096 87380 174760 +net.ipv4.tcp_wmem = 10000000 10000000 10000000 # sets min/pressure/max TCP write buffer, default 4096 16384 131072 +net.ipv4.tcp_mem = 10000000 10000000 10000000 # sets min/pressure/max TCP buffer space, default 31744 32256 32768 + +### CORE settings (mostly for socket and UDP effect) +net.core.rmem_max = 524287 # maximum receive socket buffer size, default 131071 +net.core.wmem_max = 524287 # maximum send socket buffer size, default 131071 +net.core.rmem_default = 524287 # default receive socket buffer size, default 65535 +net.core.wmem_default = 524287 # default send socket buffer size, default 65535 +net.core.optmem_max = 524287 # maximum amount of option memory buffers, default 10240 +net.core.netdev_max_backlog = 300000 # number of unprocessed input packets before kernel starts dropping them, default 300 +- END sysctl_ixgb.conf + +Edit the ixgb_perf.sh script if necessary to change eth1 to whatever interface +your ixgb driver is using. + +NOTE: Unless these scripts are added to the boot process, these changes will +only last only until the next system reboot. + + +Resolving Slow UDP Traffic +-------------------------- + +If your server does not seem to be able to receive UDP traffic as fast as it +can receive TCP traffic, it could be because Linux, by default, does not set +the network stack buffers as large as they need to be to support high UDP +transfer rates. One way to alleviate this problem is to allow more memory to +be used by the IP stack to store incoming data. + +For instance, use the commands: + sysctl -w net.core.rmem_max=262143 +and + sysctl -w net.core.rmem_default=262143 +to increase the read buffer memory max and default to 262143 (256k - 1) from +defaults of max=131071 (128k - 1) and default=65535 (64k - 1). These variables +will increase the amount of memory used by the network stack for receives, and +can be increased significantly more if necessary for your application. + +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 linux.nics@intel.com. |
