diff options
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/networking/3c509.txt | 12 | ||||
| -rw-r--r-- | Documentation/networking/Makefile | 2 | ||||
| -rw-r--r-- | Documentation/networking/bonding.txt | 42 | ||||
| -rw-r--r-- | Documentation/networking/cxacru-cf.py | 48 | ||||
| -rw-r--r-- | Documentation/networking/cxacru.txt | 16 | ||||
| -rw-r--r-- | Documentation/networking/dccp.txt | 6 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 102 | ||||
| -rwxr-xr-x | Documentation/networking/ixgbevf.txt | 90 | ||||
| -rw-r--r-- | Documentation/networking/packet_mmap.txt | 8 | ||||
| -rw-r--r-- | Documentation/networking/pktgen.txt | 8 | ||||
| -rw-r--r-- | Documentation/networking/regulatory.txt | 24 | ||||
| -rw-r--r-- | Documentation/networking/skfp.txt | 2 | ||||
| -rw-r--r-- | Documentation/networking/tcp-thin.txt | 47 | ||||
| -rw-r--r-- | Documentation/networking/timestamping/Makefile | 11 | ||||
| -rw-r--r-- | Documentation/networking/timestamping/timestamping.c | 14 |
16 files changed, 404 insertions, 30 deletions
diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX index 50189bf07d5..fe5c099b8fc 100644 --- a/Documentation/networking/00-INDEX +++ b/Documentation/networking/00-INDEX @@ -32,6 +32,8 @@ cs89x0.txt - the Crystal LAN (CS8900/20-based) Ethernet ISA adapter driver cxacru.txt - Conexant AccessRunner USB ADSL Modem +cxacru-cf.py + - Conexant AccessRunner USB ADSL Modem configuration file parser de4x5.txt - the Digital EtherWORKS DE4?? and DE5?? PCI Ethernet driver decnet.txt diff --git a/Documentation/networking/3c509.txt b/Documentation/networking/3c509.txt index 0643e3b7168..3c45d5dcd63 100644 --- a/Documentation/networking/3c509.txt +++ b/Documentation/networking/3c509.txt @@ -48,11 +48,11 @@ for LILO parameters for doing this: This configures the first found 3c509 card for IRQ 10, base I/O 0x310, and transceiver type 3 (10base2). The flag "0x3c509" must be set to avoid conflicts with other card types when overriding the I/O address. When the driver is -loaded as a module, only the IRQ and transceiver setting may be overridden. -For example, setting two cards to 10base2/IRQ10 and AUI/IRQ11 is done by using -the xcvr and irq module options: +loaded as a module, only the IRQ may be overridden. For example, +setting two cards to IRQ10 and IRQ11 is done by using the irq module +option: - options 3c509 xcvr=3,1 irq=10,11 + options 3c509 irq=10,11 (2) Full-duplex mode @@ -77,6 +77,8 @@ operation. itself full-duplex capable. This is almost certainly one of two things: a full- duplex-capable Ethernet switch (*not* a hub), or a full-duplex-capable NIC on another system that's connected directly to the 3c509B via a crossover cable. + +Full-duplex mode can be enabled using 'ethtool'. /////Extremely important caution concerning full-duplex mode///// Understand that the 3c509B's hardware's full-duplex support is much more @@ -113,6 +115,8 @@ This insured that merely upgrading the driver from an earlier version would never automatically enable full-duplex mode in an existing installation; it must always be explicitly enabled via one of these code in order to be activated. + +The transceiver type can be changed using 'ethtool'. (4a) Interpretation of error messages and common problems diff --git a/Documentation/networking/Makefile b/Documentation/networking/Makefile index 6d8af1ac56c..5aba7a33aee 100644 --- a/Documentation/networking/Makefile +++ b/Documentation/networking/Makefile @@ -6,3 +6,5 @@ hostprogs-y := ifenslave # Tell kbuild to always build the programs always := $(hostprogs-y) + +obj-m := timestamping/ diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index d5181ce9ff6..61f516b135b 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -1,7 +1,7 @@ Linux Ethernet Bonding Driver HOWTO - Latest update: 12 November 2007 + Latest update: 23 September 2009 Initial release : Thomas Davis <tadavis at lbl.gov> Corrections, HA extensions : 2000/10/03-15 : @@ -614,6 +614,46 @@ primary The primary option is only valid for active-backup mode. +primary_reselect + + Specifies the reselection policy for the primary slave. This + affects how the primary slave is chosen to become the active slave + when failure of the active slave or recovery of the primary slave + occurs. This option is designed to prevent flip-flopping between + the primary slave and other slaves. Possible values are: + + always or 0 (default) + + The primary slave becomes the active slave whenever it + comes back up. + + better or 1 + + The primary slave becomes the active slave when it comes + back up, if the speed and duplex of the primary slave is + better than the speed and duplex of the current active + slave. + + failure or 2 + + The primary slave becomes the active slave only if the + current active slave fails and the primary slave is up. + + The primary_reselect setting is ignored in two cases: + + If no slaves are active, the first slave to recover is + made the active slave. + + When initially enslaved, the primary slave is always made + the active slave. + + Changing the primary_reselect policy via sysfs will cause an + immediate selection of the best active slave according to the new + policy. This may or may not result in a change of the active + slave, depending upon the circumstances. + + This option was added for bonding version 3.6.0. + updelay Specifies the time, in milliseconds, to wait before enabling a diff --git a/Documentation/networking/cxacru-cf.py b/Documentation/networking/cxacru-cf.py new file mode 100644 index 00000000000..b41d298398c --- /dev/null +++ b/Documentation/networking/cxacru-cf.py @@ -0,0 +1,48 @@ +#!/usr/bin/env python +# Copyright 2009 Simon Arlott +# +# This program is free software; you can redistribute it and/or modify it +# under the terms of the GNU General Public License as published by the Free +# Software Foundation; either version 2 of the License, or (at your option) +# any later version. +# +# This program is distributed in the hope that it will be useful, but WITHOUT +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for +# more details. +# +# 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. +# +# Usage: cxacru-cf.py < cxacru-cf.bin +# Output: values string suitable for the sysfs adsl_config attribute +# +# Warning: cxacru-cf.bin with MD5 hash cdbac2689969d5ed5d4850f117702110 +# contains mis-aligned values which will stop the modem from being able +# to make a connection. If the first and last two bytes are removed then +# the values become valid, but the modulation will be forced to ANSI +# T1.413 only which may not be appropriate. +# +# The original binary format is a packed list of le32 values. + +import sys +import struct + +i = 0 +while True: + buf = sys.stdin.read(4) + + if len(buf) == 0: + break + elif len(buf) != 4: + sys.stdout.write("\n") + sys.stderr.write("Error: read {0} not 4 bytes\n".format(len(buf))) + sys.exit(1) + + if i > 0: + sys.stdout.write(" ") + sys.stdout.write("{0:x}={1}".format(i, struct.unpack("<I", buf)[0])) + i += 1 + +sys.stdout.write("\n") diff --git a/Documentation/networking/cxacru.txt b/Documentation/networking/cxacru.txt index b074681a963..2cce04457b4 100644 --- a/Documentation/networking/cxacru.txt +++ b/Documentation/networking/cxacru.txt @@ -4,6 +4,12 @@ While it is capable of managing/maintaining the ADSL connection without the module loaded, the device will sometimes stop responding after unloading the driver and it is necessary to unplug/remove power to the device to fix this. +Note: support for cxacru-cf.bin has been removed. It was not loaded correctly +so it had no effect on the device configuration. Fixing it could have stopped +existing devices working when an invalid configuration is supplied. + +There is a script cxacru-cf.py to convert an existing file to the sysfs form. + Detected devices will appear as ATM devices named "cxacru". In /sys/class/atm/ these are directories named cxacruN where N is the device number. A symlink named device points to the USB interface device's directory which contains @@ -15,6 +21,15 @@ several sysfs attribute files for retrieving device statistics: * adsl_headend_environment Information about the remote headend. +* adsl_config + Configuration writing interface. + Write parameters in hexadecimal format <index>=<value>, + separated by whitespace, e.g.: + "1=0 a=5" + Up to 7 parameters at a time will be sent and the modem will restart + the ADSL connection when any value is set. These are logged for future + reference. + * downstream_attenuation (dB) * downstream_bits_per_frame * downstream_rate (kbps) @@ -61,6 +76,7 @@ several sysfs attribute files for retrieving device statistics: * mac_address * modulation + "" (when not connected) "ANSI T1.413" "ITU-T G.992.1 (G.DMT)" "ITU-T G.992.2 (G.LITE)" diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt index b132e4a3cf0..a62fdf7a6bf 100644 --- a/Documentation/networking/dccp.txt +++ b/Documentation/networking/dccp.txt @@ -58,8 +58,10 @@ DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet size (application payload size) in bytes, see RFC 4340, section 14. DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs -supported by the endpoint (see include/linux/dccp.h for symbolic constants). -The caller needs to provide a sufficiently large (> 2) array of type uint8_t. +supported by the endpoint. The option value is an array of type uint8_t whose +size is passed as option length. The minimum array size is 4 elements, the +value returned in the optlen argument always reflects the true number of +built-in CCIDs. DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same time, combining the operation of the next two socket options. This option is diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index fbe427a6580..8b72c88ba21 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -164,6 +164,14 @@ tcp_congestion_control - STRING additional choices may be available based on kernel configuration. Default is set as part of kernel configuration. +tcp_cookie_size - INTEGER + Default size of TCP Cookie Transactions (TCPCT) option, that may be + overridden on a per socket basis by the TCPCT socket option. + Values greater than the maximum (16) are interpreted as the maximum. + Values greater than zero and less than the minimum (8) are interpreted + as the minimum. Odd values are interpreted as the next even value. + Default: 0 (off). + tcp_dsack - BOOLEAN Allows TCP to send "duplicate" SACKs. @@ -479,6 +487,30 @@ tcp_dma_copybreak - INTEGER and CONFIG_NET_DMA is enabled. Default: 4096 +tcp_thin_linear_timeouts - BOOLEAN + Enable dynamic triggering of linear timeouts for thin streams. + If set, a check is performed upon retransmission by timeout to + determine if the stream is thin (less than 4 packets in flight). + As long as the stream is found to be thin, up to 6 linear + timeouts may be performed before exponential backoff mode is + initiated. This improves retransmission latency for + non-aggressive thin streams, often found to be time-dependent. + For more information on thin streams, see + Documentation/networking/tcp-thin.txt + Default: 0 + +tcp_thin_dupack - BOOLEAN + Enable dynamic triggering of retransmissions after one dupACK + for thin streams. If set, a check is performed upon reception + of a dupACK to determine if the stream is thin (less than 4 + packets in flight). As long as the stream is found to be thin, + data is retransmitted on the first received dupACK. This + improves retransmission latency for non-aggressive thin + streams, often found to be time-dependent. + For more information on thin streams, see + Documentation/networking/tcp-thin.txt + Default: 0 + UDP variables: udp_mem - vector of 3 INTEGERs: min, pressure, max @@ -684,6 +716,25 @@ proxy_arp - BOOLEAN conf/{all,interface}/proxy_arp is set to TRUE, it will be disabled otherwise +proxy_arp_pvlan - BOOLEAN + Private VLAN proxy arp. + Basically allow proxy arp replies back to the same interface + (from which the ARP request/solicitation was received). + + This is done to support (ethernet) switch features, like RFC + 3069, where the individual ports are NOT allowed to + communicate with each other, but they are allowed to talk to + the upstream router. As described in RFC 3069, it is possible + to allow these hosts to communicate through the upstream + router by proxy_arp'ing. Don't need to be used together with + proxy_arp. + + This technology is known by different names: + In RFC 3069 it is called VLAN Aggregation. + Cisco and Allied Telesyn call it Private VLAN. + Hewlett-Packard call it Source-Port filtering or port-isolation. + Ericsson call it MAC-Forced Forwarding (RFC Draft). + shared_media - BOOLEAN Send(router) or accept(host) RFC1620 shared media redirects. Overrides ip_secure_redirects. @@ -723,6 +774,12 @@ accept_source_route - BOOLEAN default TRUE (router) FALSE (host) +accept_local - BOOLEAN + Accept packets with local source addresses. In combination with + suitable routing, this can be used to direct packets between two + local interfaces over the wire and have them accepted properly. + default FALSE + rp_filter - INTEGER 0 - No source validation. 1 - Strict mode as defined in RFC3704 Strict Reverse Path @@ -738,8 +795,8 @@ rp_filter - INTEGER to prevent IP spoofing from DDos attacks. If using asymmetric routing or other complicated routing, then loose mode is recommended. - conf/all/rp_filter must also be set to non-zero to do source validation - on the interface + The max value from conf/{all,interface}/rp_filter is used + when doing source validation on the {interface}. Default value is 0. Note that some distributions enable it in startup scripts. @@ -819,9 +876,18 @@ arp_notify - BOOLEAN or hardware address changes. arp_accept - BOOLEAN - Define behavior when gratuitous arp replies are received: - 0 - drop gratuitous arp frames - 1 - accept gratuitous arp frames + Define behavior for gratuitous ARP frames who's IP is not + already present in the ARP table: + 0 - don't create new entries in the ARP table + 1 - create new entries in the ARP table + + Both replies and requests type gratuitous arp will trigger the + ARP table to be updated, if this setting is on. + + If the ARP table already contains the IP address of the + gratuitous arp frame, the arp table will be updated regardless + if this setting is on or off. + app_solicit - INTEGER The maximum number of probes to send to the user space ARP daemon @@ -1060,10 +1126,10 @@ regen_max_retry - INTEGER Default: 5 max_addresses - INTEGER - Number of maximum addresses per interface. 0 disables limitation. - It is recommended not set too large value (or 0) because it would - be too easy way to crash kernel to allow to create too much of - autoconfigured addresses. + Maximum number of autoconfigured addresses per interface. Setting + to zero disables the limitation. It is not recommended to set this + value too large (or to zero) because it would be an easy way to + crash the kernel by allowing too many addresses to be created. Default: 16 disable_ipv6 - BOOLEAN @@ -1086,6 +1152,24 @@ accept_dad - INTEGER 2: Enable DAD, and disable IPv6 operation if MAC-based duplicate link-local address has been found. +force_tllao - BOOLEAN + Enable sending the target link-layer address option even when + responding to a unicast neighbor solicitation. + Default: FALSE + + Quoting from RFC 2461, section 4.4, Target link-layer address: + + "The option MUST be included for multicast solicitations in order to + avoid infinite Neighbor Solicitation "recursion" when the peer node + does not have a cache entry to return a Neighbor Advertisements + message. When responding to unicast solicitations, the option can be + omitted since the sender of the solicitation has the correct link- + layer address; otherwise it would not have be able to send the unicast + solicitation in the first place. However, including the link-layer + address in this case adds little overhead and eliminates a potential + race condition where the sender deletes the cached link-layer address + prior to receiving a response to a previous solicitation." + icmp/*: ratelimit - INTEGER Limit the maximal rates for sending ICMPv6 packets. diff --git a/Documentation/networking/ixgbevf.txt b/Documentation/networking/ixgbevf.txt new file mode 100755 index 00000000000..19015de6725 --- /dev/null +++ b/Documentation/networking/ixgbevf.txt @@ -0,0 +1,90 @@ +Linux* Base Driver for Intel(R) Network Connection +================================================== + +November 24, 2009 + +Contents +======== + +- In This Release +- Identifying Your Adapter +- Known Issues/Troubleshooting +- Support + +In This Release +=============== + +This file describes the ixgbevf Linux* Base Driver for Intel Network +Connection. + +The ixgbevf driver supports 82599-based virtual function devices that can only +be activated on kernels with CONFIG_PCI_IOV enabled. + +The ixgbevf driver supports virtual functions generated by the ixgbe driver +with a max_vfs value of 1 or greater. + +The guest OS loading the ixgbevf driver must support MSI-X interrupts. + +VLANs: There is a limit of a total of 32 shared VLANs to 1 or more VFs. + +Identifying Your Adapter +======================== + +For more information on how to identify your adapter, go to the Adapter & +Driver ID Guide at: + + http://support.intel.com/support/network/sb/CS-008441.htm + +Known Issues/Troubleshooting +============================ + + Unloading Physical Function (PF) Driver Causes System Reboots When VM is + Running and VF is Loaded on the VM + ------------------------------------------------------------------------ + Do not unload the PF driver (ixgbe) while VFs are assigned to guests. + +Support +======= + +For general information, go to the Intel support website at: + + http://support.intel.com + +or the Intel Wired Networking project hosted by Sourceforge at: + + http://sourceforge.net/projects/e1000 + +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 e1000-devel@lists.sf.net + +License +======= + +Intel 10 Gigabit Linux driver. +Copyright(c) 1999 - 2009 Intel Corporation. + +This program is free software; you can redistribute it and/or modify it +under the terms and conditions of the GNU General Public License, +version 2, as published by the Free Software Foundation. + +This program is distributed in the hope it will be useful, but WITHOUT +ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for +more details. + +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., +51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + +The full GNU General Public License is included in this distribution in +the file called "COPYING". + +Trademarks +========== + +Intel, Itanium, and Pentium are trademarks or registered trademarks of +Intel Corporation or its subsidiaries in the United States and other +countries. + +* Other names and brands may be claimed as the property of others. diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index a22fd85e379..09ab0d29032 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -2,7 +2,7 @@ + ABSTRACT -------------------------------------------------------------------------------- -This file documents the CONFIG_PACKET_MMAP option available with the PACKET +This file documents the mmap() facility available with the PACKET socket interface on 2.4 and 2.6 kernels. This type of sockets is used for capture network traffic with utilities like tcpdump or any other that needs raw access to network interface. @@ -44,7 +44,7 @@ enabled. For transmission, check the MTU (Maximum Transmission Unit) used and supported by devices of your network. -------------------------------------------------------------------------------- -+ How to use CONFIG_PACKET_MMAP to improve capture process ++ How to use mmap() to improve capture process -------------------------------------------------------------------------------- From the user standpoint, you should use the higher level libpcap library, which @@ -64,7 +64,7 @@ the low level details or want to improve libpcap by including PACKET_MMAP support. -------------------------------------------------------------------------------- -+ How to use CONFIG_PACKET_MMAP directly to improve capture process ++ How to use mmap() directly to improve capture process -------------------------------------------------------------------------------- From the system calls stand point, the use of PACKET_MMAP involves @@ -105,7 +105,7 @@ also the mapping of the circular buffer in the user process and the use of this buffer. -------------------------------------------------------------------------------- -+ How to use CONFIG_PACKET_MMAP directly to improve transmission process ++ How to use mmap() directly to improve transmission process -------------------------------------------------------------------------------- Transmission process is similar to capture as shown below. diff --git a/Documentation/networking/pktgen.txt b/Documentation/networking/pktgen.txt index c6cf4a3c16e..61bb645d50e 100644 --- a/Documentation/networking/pktgen.txt +++ b/Documentation/networking/pktgen.txt @@ -90,6 +90,11 @@ Examples: pgset "dstmac 00:00:00:00:00:00" sets MAC destination address pgset "srcmac 00:00:00:00:00:00" sets MAC source address + pgset "queue_map_min 0" Sets the min value of tx queue interval + pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices + To select queue 1 of a given device, + use queue_map_min=1 and queue_map_max=1 + pgset "src_mac_count 1" Sets the number of MACs we'll range through. The 'minimum' MAC is what you set with srcmac. @@ -101,6 +106,9 @@ Examples: IPDST_RND, UDPSRC_RND, UDPDST_RND, MACSRC_RND, MACDST_RND MPLS_RND, VID_RND, SVID_RND + QUEUE_MAP_RND # queue map random + QUEUE_MAP_CPU # queue map mirrors smp_processor_id() + pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then cycle through the port range. diff --git a/Documentation/networking/regulatory.txt b/Documentation/networking/regulatory.txt index ee31369e9e5..9551622d0a7 100644 --- a/Documentation/networking/regulatory.txt +++ b/Documentation/networking/regulatory.txt @@ -188,3 +188,27 @@ Then in some part of your code after your wiphy has been registered: &mydriver_jp_regdom.reg_rules[i], sizeof(struct ieee80211_reg_rule)); regulatory_struct_hint(rd); + +Statically compiled regulatory database +--------------------------------------- + +In most situations the userland solution using CRDA as described +above is the preferred solution. However in some cases a set of +rules built into the kernel itself may be desirable. To account +for this situation, a configuration option has been provided +(i.e. CONFIG_CFG80211_INTERNAL_REGDB). With this option enabled, +the wireless database information contained in net/wireless/db.txt is +used to generate a data structure encoded in net/wireless/regdb.c. +That option also enables code in net/wireless/reg.c which queries +the data in regdb.c as an alternative to using CRDA. + +The file net/wireless/db.txt should be kept up-to-date with the db.txt +file available in the git repository here: + + git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-regdb.git + +Again, most users in most situations should be using the CRDA package +provided with their distribution, and in most other situations users +should be building and using CRDA on their own rather than using +this option. If you are not absolutely sure that you should be using +CONFIG_CFG80211_INTERNAL_REGDB then _DO_NOT_USE_IT_. diff --git a/Documentation/networking/skfp.txt b/Documentation/networking/skfp.txt index abfddf81e34..203ec66c9fb 100644 --- a/Documentation/networking/skfp.txt +++ b/Documentation/networking/skfp.txt @@ -68,7 +68,7 @@ Compaq adapters (not tested): ======================= From v2.01 on, the driver is integrated in the linux kernel sources. -Therefor, the installation is the same as for any other adapter +Therefore, the installation is the same as for any other adapter supported by the kernel. Refer to the manual of your distribution about the installation of network adapters. diff --git a/Documentation/networking/tcp-thin.txt b/Documentation/networking/tcp-thin.txt new file mode 100644 index 00000000000..151e229980f --- /dev/null +++ b/Documentation/networking/tcp-thin.txt @@ -0,0 +1,47 @@ +Thin-streams and TCP +==================== +A wide range of Internet-based services that use reliable transport +protocols display what we call thin-stream properties. This means +that the application sends data with such a low rate that the +retransmission mechanisms of the transport protocol are not fully +effective. In time-dependent scenarios (like online games, control +systems, stock trading etc.) where the user experience depends +on the data delivery latency, packet loss can be devastating for +the service quality. Extreme latencies are caused by TCP's +dependency on the arrival of new data from the application to trigger +retransmissions effectively through fast retransmit instead of +waiting for long timeouts. + +After analysing a large number of time-dependent interactive +applications, we have seen that they often produce thin streams +and also stay with this traffic pattern throughout its entire +lifespan. The combination of time-dependency and the fact that the +streams provoke high latencies when using TCP is unfortunate. + +In order to reduce application-layer latency when packets are lost, +a set of mechanisms has been made, which address these latency issues +for thin streams. In short, if the kernel detects a thin stream, +the retransmission mechanisms are modified in the following manner: + +1) If the stream is thin, fast retransmit on the first dupACK. +2) If the stream is thin, do not apply exponential backoff. + +These enhancements are applied only if the stream is detected as +thin. This is accomplished by defining a threshold for the number +of packets in flight. If there are less than 4 packets in flight, +fast retransmissions can not be triggered, and the stream is prone +to experience high retransmission latencies. + +Since these mechanisms are targeted at time-dependent applications, +they must be specifically activated by the application using the +TCP_THIN_LINEAR_TIMEOUTS and TCP_THIN_DUPACK IOCTLS or the +tcp_thin_linear_timeouts and tcp_thin_dupack sysctls. Both +modifications are turned off by default. + +References +========== +More information on the modifications, as well as a wide range of +experimental data can be found here: +"Improving latency for interactive, thin-stream applications over +reliable transport" +http://simula.no/research/nd/publications/Simula.nd.477/simula_pdf_file diff --git a/Documentation/networking/timestamping/Makefile b/Documentation/networking/timestamping/Makefile index 2a1489fdc03..e79973443e9 100644 --- a/Documentation/networking/timestamping/Makefile +++ b/Documentation/networking/timestamping/Makefile @@ -1,6 +1,13 @@ -CPPFLAGS = -I../../../include +# kbuild trick to avoid linker error. Can be omitted if a module is built. +obj- := dummy.o -timestamping: timestamping.c +# List of programs to build +hostprogs-y := timestamping + +# Tell kbuild to always build the programs +always := $(hostprogs-y) + +HOSTCFLAGS_timestamping.o += -I$(objtree)/usr/include clean: rm -f timestamping diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c index 43d14310421..8ba82bfe6a3 100644 --- a/Documentation/networking/timestamping/timestamping.c +++ b/Documentation/networking/timestamping/timestamping.c @@ -41,9 +41,9 @@ #include <arpa/inet.h> #include <net/if.h> -#include "asm/types.h" -#include "linux/net_tstamp.h" -#include "linux/errqueue.h" +#include <asm/types.h> +#include <linux/net_tstamp.h> +#include <linux/errqueue.h> #ifndef SO_TIMESTAMPING # define SO_TIMESTAMPING 37 @@ -164,7 +164,7 @@ static void printpacket(struct msghdr *msg, int res, gettimeofday(&now, 0); - printf("%ld.%06ld: received %s data, %d bytes from %s, %d bytes control messages\n", + printf("%ld.%06ld: received %s data, %d bytes from %s, %zu bytes control messages\n", (long)now.tv_sec, (long)now.tv_usec, (recvmsg_flags & MSG_ERRQUEUE) ? "error" : "regular", res, @@ -173,7 +173,7 @@ static void printpacket(struct msghdr *msg, int res, for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { - printf(" cmsg len %d: ", cmsg->cmsg_len); + printf(" cmsg len %zu: ", cmsg->cmsg_len); switch (cmsg->cmsg_level) { case SOL_SOCKET: printf("SOL_SOCKET "); @@ -370,7 +370,7 @@ int main(int argc, char **argv) } sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); - if (socket < 0) + if (sock < 0) bail("socket"); memset(&device, 0, sizeof(device)); @@ -381,7 +381,7 @@ int main(int argc, char **argv) memset(&hwtstamp, 0, sizeof(hwtstamp)); strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name)); hwtstamp.ifr_data = (void *)&hwconfig; - memset(&hwconfig, 0, sizeof(&hwconfig)); + memset(&hwconfig, 0, sizeof(hwconfig)); hwconfig.tx_type = (so_timestamping_flags & SOF_TIMESTAMPING_TX_HARDWARE) ? HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF; |